diff --git a/boilerplates/boilerplate-react-ts/server/index.ts b/boilerplates/boilerplate-react-ts/server/index.ts
index e8729bd872..dbe5a2f2c2 100644
--- a/boilerplates/boilerplate-react-ts/server/index.ts
+++ b/boilerplates/boilerplate-react-ts/server/index.ts
@@ -14,7 +14,7 @@
 import express from 'express'
 import compression from 'compression'
 import { renderPage } from 'vike/server'
-import { root } from './root.js'
+import { root } from './root'
 const isProduction = process.env.NODE_ENV === 'production'
 
 startServer()
diff --git a/boilerplates/boilerplate-react/server/index.js b/boilerplates/boilerplate-react/server/index.js
index e8729bd872..dbe5a2f2c2 100644
--- a/boilerplates/boilerplate-react/server/index.js
+++ b/boilerplates/boilerplate-react/server/index.js
@@ -14,7 +14,7 @@
 import express from 'express'
 import compression from 'compression'
 import { renderPage } from 'vike/server'
-import { root } from './root.js'
+import { root } from './root'
 const isProduction = process.env.NODE_ENV === 'production'
 
 startServer()
diff --git a/boilerplates/boilerplate-vue-ts/server/index.ts b/boilerplates/boilerplate-vue-ts/server/index.ts
index e8729bd872..dbe5a2f2c2 100644
--- a/boilerplates/boilerplate-vue-ts/server/index.ts
+++ b/boilerplates/boilerplate-vue-ts/server/index.ts
@@ -14,7 +14,7 @@
 import express from 'express'
 import compression from 'compression'
 import { renderPage } from 'vike/server'
-import { root } from './root.js'
+import { root } from './root'
 const isProduction = process.env.NODE_ENV === 'production'
 
 startServer()
diff --git a/boilerplates/boilerplate-vue/server/index.js b/boilerplates/boilerplate-vue/server/index.js
index e8729bd872..dbe5a2f2c2 100644
--- a/boilerplates/boilerplate-vue/server/index.js
+++ b/boilerplates/boilerplate-vue/server/index.js
@@ -14,7 +14,7 @@
 import express from 'express'
 import compression from 'compression'
 import { renderPage } from 'vike/server'
-import { root } from './root.js'
+import { root } from './root'
 const isProduction = process.env.NODE_ENV === 'production'
 
 startServer()
diff --git a/vike/__internal/index.ts b/vike/__internal/index.ts
index c9cfa6e0c7..5346aa9d84 100644
--- a/vike/__internal/index.ts
+++ b/vike/__internal/index.ts
@@ -5,12 +5,12 @@ export type { PageRoutes, PageFile, PageConfigRuntime as PageConfig }
 // Internals needed by nitedani's experimental implementation of vike-telefunc
 export { getPageFilesAllSafe }
 
-import { route as routeInternal, type PageRoutes } from '../shared/route/index.js'
-import { getPageFilesAll, type PageFile } from '../shared/getPageFiles.js'
-import { getGlobalContext, initGlobalContext_getGlobalContextAsync } from '../node/runtime/globalContext.js'
-import { handleNodeEnv_vitePluginVercel } from '../utils/assertNodeEnv.js'
-import { getRenderContext } from '../node/runtime/renderPage/renderPageAlreadyRouted.js'
-import { PageConfigRuntime } from '../shared/page-configs/PageConfig.js'
+import { route as routeInternal, type PageRoutes } from '../shared/route/index'
+import { getPageFilesAll, type PageFile } from '../shared/getPageFiles'
+import { getGlobalContext, initGlobalContext_getGlobalContextAsync } from '../node/runtime/globalContext'
+import { handleNodeEnv_vitePluginVercel } from '../utils/assertNodeEnv'
+import { getRenderContext } from '../node/runtime/renderPage/renderPageAlreadyRouted'
+import { PageConfigRuntime } from '../shared/page-configs/PageConfig'
 
 /**
  * Used by {@link https://github.com/magne4000/vite-plugin-vercel|vite-plugin-vercel}
diff --git a/vike/client/client-routing-runtime/createPageContext.ts b/vike/client/client-routing-runtime/createPageContext.ts
index 3368146615..af1bd2d401 100644
--- a/vike/client/client-routing-runtime/createPageContext.ts
+++ b/vike/client/client-routing-runtime/createPageContext.ts
@@ -1,10 +1,10 @@
 export { createPageContext }
 
-import { getPageContextUrlComputed } from '../../shared/getPageContextUrlComputed.js'
-import { getPageFilesAll } from '../../shared/getPageFiles.js'
-import { loadPageRoutes } from '../../shared/route/loadPageRoutes.js'
-import { getBaseServer } from './getBaseServer.js'
-import { assert, isBaseServer, PromiseType, getGlobalObject, objectAssign } from './utils.js'
+import { getPageContextUrlComputed } from '../../shared/getPageContextUrlComputed'
+import { getPageFilesAll } from '../../shared/getPageFiles'
+import { loadPageRoutes } from '../../shared/route/loadPageRoutes'
+import { getBaseServer } from './getBaseServer'
+import { assert, isBaseServer, PromiseType, getGlobalObject, objectAssign } from './utils'
 const globalObject = getGlobalObject<{
   pageFilesData?: PromiseType<ReturnType<typeof getPageFilesAll>>
 }>('createPageContext.ts', {})
diff --git a/vike/client/client-routing-runtime/entry.ts b/vike/client/client-routing-runtime/entry.ts
index 0e78284860..cf6a84d629 100644
--- a/vike/client/client-routing-runtime/entry.ts
+++ b/vike/client/client-routing-runtime/entry.ts
@@ -1,10 +1,10 @@
-import { assertClientRouting } from '../../utils/assertRoutingType.js'
+import { assertClientRouting } from '../../utils/assertRoutingType'
 assertClientRouting()
 
 import './pageFiles'
-import { initClientRouter } from './initClientRouter.js'
-import { assertSingleInstance_onClientEntryClientRouting } from './utils.js'
-import { removeFoucBuster } from '../shared/removeFoucBuster.js'
+import { initClientRouter } from './initClientRouter'
+import { assertSingleInstance_onClientEntryClientRouting } from './utils'
+import { removeFoucBuster } from '../shared/removeFoucBuster'
 // @ts-ignore Since dist/cjs/client/ is never used, we can ignore this error.
 const isProd: boolean = import.meta.env.PROD
 assertSingleInstance_onClientEntryClientRouting(isProd)
diff --git a/vike/client/client-routing-runtime/getBaseServer.ts b/vike/client/client-routing-runtime/getBaseServer.ts
index da4a4392db..644ee6fa11 100644
--- a/vike/client/client-routing-runtime/getBaseServer.ts
+++ b/vike/client/client-routing-runtime/getBaseServer.ts
@@ -1,6 +1,6 @@
 export { getBaseServer }
 
-import { assert } from '../server-routing-runtime/utils.js'
+import { assert } from '../server-routing-runtime/utils'
 
 function getBaseServer(): string {
   // @ts-ignore Since dist/cjs/client/ is never used, we can ignore this error.
diff --git a/vike/client/client-routing-runtime/getPageContext/removeBuiltInOverrides.ts b/vike/client/client-routing-runtime/getPageContext/removeBuiltInOverrides.ts
index c082c596ea..0bf8af3f3c 100644
--- a/vike/client/client-routing-runtime/getPageContext/removeBuiltInOverrides.ts
+++ b/vike/client/client-routing-runtime/getPageContext/removeBuiltInOverrides.ts
@@ -1,6 +1,6 @@
 export { removeBuiltInOverrides }
 
-import { assert, assertWarning } from '../utils.js'
+import { assert, assertWarning } from '../utils'
 
 const BUILT_IN_CLIENT_ROUTER = ['urlPathname', 'urlParsed'] as const
 const BUILT_IN_CLIENT = ['Page', 'pageExports', 'exports'] as const
diff --git a/vike/client/client-routing-runtime/getPageContextCurrent.ts b/vike/client/client-routing-runtime/getPageContextCurrent.ts
index 2fd87cf968..c402b9b951 100644
--- a/vike/client/client-routing-runtime/getPageContextCurrent.ts
+++ b/vike/client/client-routing-runtime/getPageContextCurrent.ts
@@ -1,8 +1,8 @@
 export { setPageContextCurrent }
 export { getPageContextCurrent }
 
-import { getGlobalObject } from './utils.js'
-import type { PageContextExports } from '../../shared/getPageFiles.js'
+import { getGlobalObject } from './utils'
+import type { PageContextExports } from '../../shared/getPageFiles'
 
 type PageContextCurrent = PageContextExports & {
   urlPathname: string
diff --git a/vike/client/client-routing-runtime/getPageContextFromHooks.ts b/vike/client/client-routing-runtime/getPageContextFromHooks.ts
index a50b65bd0c..b0df5c0516 100644
--- a/vike/client/client-routing-runtime/getPageContextFromHooks.ts
+++ b/vike/client/client-routing-runtime/getPageContextFromHooks.ts
@@ -16,23 +16,23 @@ import {
   executeHook,
   isObject,
   getGlobalObject
-} from './utils.js'
+} from './utils'
 import { parse } from '@brillout/json-serializer/parse'
-import { getPageContextSerializedInHtml } from '../shared/getPageContextSerializedInHtml.js'
-import type { PageContextExports, PageFile } from '../../shared/getPageFiles.js'
-import { analyzePageServerSide } from '../../shared/getPageFiles/analyzePageServerSide.js'
-import { getHook } from '../../shared/hooks/getHook.js'
-import { preparePageContextForUserConsumptionClientSide } from '../shared/preparePageContextForUserConsumptionClientSide.js'
-import { removeBuiltInOverrides } from './getPageContext/removeBuiltInOverrides.js'
-import { getPageContextRequestUrl } from '../../shared/getPageContextRequestUrl.js'
-import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig.js'
-import { getPageConfig } from '../../shared/page-configs/helpers.js'
-import { getConfigValueRuntime } from '../../shared/page-configs/getConfigValue.js'
-import { assertOnBeforeRenderHookReturn } from '../../shared/assertOnBeforeRenderHookReturn.js'
-import { executeGuardHook } from '../../shared/route/executeGuardHook.js'
-import { AbortRender, isAbortPageContext } from '../../shared/route/abort.js'
-import { pageContextInitIsPassedToClient } from '../../shared/misc/pageContextInitIsPassedToClient.js'
-import { isServerSideError } from '../../shared/misc/isServerSideError.js'
+import { getPageContextSerializedInHtml } from '../shared/getPageContextSerializedInHtml'
+import type { PageContextExports, PageFile } from '../../shared/getPageFiles'
+import { analyzePageServerSide } from '../../shared/getPageFiles/analyzePageServerSide'
+import { getHook } from '../../shared/hooks/getHook'
+import { preparePageContextForUserConsumptionClientSide } from '../shared/preparePageContextForUserConsumptionClientSide'
+import { removeBuiltInOverrides } from './getPageContext/removeBuiltInOverrides'
+import { getPageContextRequestUrl } from '../../shared/getPageContextRequestUrl'
+import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig'
+import { getPageConfig } from '../../shared/page-configs/helpers'
+import { getConfigValueRuntime } from '../../shared/page-configs/getConfigValue'
+import { assertOnBeforeRenderHookReturn } from '../../shared/assertOnBeforeRenderHookReturn'
+import { executeGuardHook } from '../../shared/route/executeGuardHook'
+import { AbortRender, isAbortPageContext } from '../../shared/route/abort'
+import { pageContextInitIsPassedToClient } from '../../shared/misc/pageContextInitIsPassedToClient'
+import { isServerSideError } from '../../shared/misc/isServerSideError'
 const globalObject = getGlobalObject<{ pageContextInitIsPassedToClient?: true }>('router/getPageContext.ts', {})
 
 // TODO/eventually: rename
diff --git a/vike/client/client-routing-runtime/history.ts b/vike/client/client-routing-runtime/history.ts
index e3ad965840..485e0424fb 100644
--- a/vike/client/client-routing-runtime/history.ts
+++ b/vike/client/client-routing-runtime/history.ts
@@ -4,7 +4,7 @@ export { saveScrollPosition }
 export type { HistoryInfo }
 export type { ScrollPosition }
 
-import { assert, assertUsage, getCurrentUrl, getGlobalObject, hasProp, isObject } from './utils.js'
+import { assert, assertUsage, getCurrentUrl, getGlobalObject, hasProp, isObject } from './utils'
 
 init()
 const globalObject = getGlobalObject('history.ts', { previous: getHistoryInfo() })
diff --git a/vike/client/client-routing-runtime/index.ts b/vike/client/client-routing-runtime/index.ts
index 0f276c35cc..4e82181e2c 100644
--- a/vike/client/client-routing-runtime/index.ts
+++ b/vike/client/client-routing-runtime/index.ts
@@ -4,13 +4,13 @@
 //   import { navigate, prefetch } from 'vike'
 // Use package.json#exports to make the imports isomorphic.
 
-export { navigate, reload } from './navigate.js'
-export { prefetch } from './prefetch.js'
-export { onPopState } from './initOnPopState.js'
-export { PROJECT_VERSION as version } from './utils.js'
+export { navigate, reload } from './navigate'
+export { prefetch } from './prefetch'
+export { onPopState } from './initOnPopState'
+export { PROJECT_VERSION as version } from './utils'
 
 // TODO/v1-release: remove this
-import type { PageContextBuiltInClientWithClientRouting } from '../../shared/types.js'
+import type { PageContextBuiltInClientWithClientRouting } from '../../shared/types'
 /** @deprecated
  * Replace:
  *   ```
diff --git a/vike/client/client-routing-runtime/initClientRouter.ts b/vike/client/client-routing-runtime/initClientRouter.ts
index 581caf37d1..989eac131c 100644
--- a/vike/client/client-routing-runtime/initClientRouter.ts
+++ b/vike/client/client-routing-runtime/initClientRouter.ts
@@ -1,12 +1,12 @@
 export { initClientRouter }
 
-import { assert } from './utils.js'
-import { getRenderCount, renderPageClientSide } from './renderPageClientSide.js'
-import { initOnPopState } from './initOnPopState.js'
-import { initOnLinkClick } from './initOnLinkClick.js'
-import { setupNativeScrollRestoration } from './scrollRestoration.js'
-import { autoSaveScrollPosition } from './setScrollPosition.js'
-import { initLinkPrefetchHandlers } from './prefetch.js'
+import { assert } from './utils'
+import { getRenderCount, renderPageClientSide } from './renderPageClientSide'
+import { initOnPopState } from './initOnPopState'
+import { initOnLinkClick } from './initOnLinkClick'
+import { setupNativeScrollRestoration } from './scrollRestoration'
+import { autoSaveScrollPosition } from './setScrollPosition'
+import { initLinkPrefetchHandlers } from './prefetch'
 
 async function initClientRouter() {
   // Init navigation history and scroll restoration
diff --git a/vike/client/client-routing-runtime/initOnLinkClick.ts b/vike/client/client-routing-runtime/initOnLinkClick.ts
index 1bb28181b7..e045fc4a6d 100644
--- a/vike/client/client-routing-runtime/initOnLinkClick.ts
+++ b/vike/client/client-routing-runtime/initOnLinkClick.ts
@@ -2,10 +2,10 @@
 
 export { initOnLinkClick }
 
-import { assert } from './utils.js'
-import { skipLink } from './skipLink.js'
-import { renderPageClientSide } from './renderPageClientSide.js'
-import type { ScrollTarget } from './setScrollPosition.js'
+import { assert } from './utils'
+import { skipLink } from './skipLink'
+import { renderPageClientSide } from './renderPageClientSide'
+import type { ScrollTarget } from './setScrollPosition'
 
 function initOnLinkClick() {
   document.addEventListener('click', handler)
diff --git a/vike/client/client-routing-runtime/initOnPopState.ts b/vike/client/client-routing-runtime/initOnPopState.ts
index e585121b25..18e18635c1 100644
--- a/vike/client/client-routing-runtime/initOnPopState.ts
+++ b/vike/client/client-routing-runtime/initOnPopState.ts
@@ -1,10 +1,10 @@
 export { initOnPopState }
 export { onPopState }
 
-import { assertWarning, getGlobalObject } from './utils.js'
-import { onPopStateBegin, type HistoryInfo } from './history.js'
-import { renderPageClientSide } from './renderPageClientSide.js'
-import { type ScrollTarget, setScrollPosition } from './setScrollPosition.js'
+import { assertWarning, getGlobalObject } from './utils'
+import { onPopStateBegin, type HistoryInfo } from './history'
+import { renderPageClientSide } from './renderPageClientSide'
+import { type ScrollTarget, setScrollPosition } from './setScrollPosition'
 
 const globalObject = getGlobalObject('initOnPopState.ts', { listeners: [] as Listener[] })
 
diff --git a/vike/client/client-routing-runtime/isClientSideRoutable.ts b/vike/client/client-routing-runtime/isClientSideRoutable.ts
index 625e385e22..d0bf2b4b87 100644
--- a/vike/client/client-routing-runtime/isClientSideRoutable.ts
+++ b/vike/client/client-routing-runtime/isClientSideRoutable.ts
@@ -1,10 +1,10 @@
 export { isClientSideRoutable }
 
-import { analyzePageClientSideInit } from '../../shared/getPageFiles/analyzePageClientSide.js'
-import { findPageConfig } from '../../shared/page-configs/findPageConfig.js'
-import { analyzeClientSide } from '../../shared/getPageFiles/analyzeClientSide.js'
-import type { PageFile } from '../../shared/getPageFiles.js'
-import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig.js'
+import { analyzePageClientSideInit } from '../../shared/getPageFiles/analyzePageClientSide'
+import { findPageConfig } from '../../shared/page-configs/findPageConfig'
+import { analyzeClientSide } from '../../shared/getPageFiles/analyzeClientSide'
+import type { PageFile } from '../../shared/getPageFiles'
+import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig'
 
 type PageContextPageFiles = {
   _pageFilesAll: PageFile[]
diff --git a/vike/client/client-routing-runtime/navigate.ts b/vike/client/client-routing-runtime/navigate.ts
index 6b0d64e6e6..3e0bc9f9cf 100644
--- a/vike/client/client-routing-runtime/navigate.ts
+++ b/vike/client/client-routing-runtime/navigate.ts
@@ -1,10 +1,10 @@
 export { navigate }
 export { reload }
 
-import { normalizeUrlArgument } from './normalizeUrlArgument.js'
-import { firstRenderStartPromise, renderPageClientSide } from './renderPageClientSide.js'
-import type { ScrollTarget } from './setScrollPosition.js'
-import { assertClientRouting, getCurrentUrl } from './utils.js'
+import { normalizeUrlArgument } from './normalizeUrlArgument'
+import { firstRenderStartPromise, renderPageClientSide } from './renderPageClientSide'
+import type { ScrollTarget } from './setScrollPosition'
+import { assertClientRouting, getCurrentUrl } from './utils'
 
 assertClientRouting()
 
diff --git a/vike/client/client-routing-runtime/normalizeUrlArgument.ts b/vike/client/client-routing-runtime/normalizeUrlArgument.ts
index f1e4c43214..7c8aa21829 100644
--- a/vike/client/client-routing-runtime/normalizeUrlArgument.ts
+++ b/vike/client/client-routing-runtime/normalizeUrlArgument.ts
@@ -1,6 +1,6 @@
 export { normalizeUrlArgument }
 
-import { assertUsage, isUrl, isUrlPathnameRelative } from './utils.js'
+import { assertUsage, isUrl, isUrlPathnameRelative } from './utils'
 
 function normalizeUrlArgument(url: string, fnName: 'prefetch' | 'navigate'): string {
   // Succinct error message to save client-side KBs
diff --git a/vike/client/client-routing-runtime/onLoad.ts b/vike/client/client-routing-runtime/onLoad.ts
index 95b8119aa8..fb0cf40c53 100644
--- a/vike/client/client-routing-runtime/onLoad.ts
+++ b/vike/client/client-routing-runtime/onLoad.ts
@@ -1,7 +1,7 @@
 export { onLoad }
 
-import { assertIsBrowser } from '../../utils/assertIsBrowser.js'
-import { assertClientRouting } from '../../utils/assertRoutingType.js'
+import { assertIsBrowser } from '../../utils/assertIsBrowser'
+import { assertClientRouting } from '../../utils/assertRoutingType'
 
 function onLoad() {
   assertIsBrowser()
diff --git a/vike/client/client-routing-runtime/pageFiles.ts b/vike/client/client-routing-runtime/pageFiles.ts
index dac3dc2001..caf59b4e67 100644
--- a/vike/client/client-routing-runtime/pageFiles.ts
+++ b/vike/client/client-routing-runtime/pageFiles.ts
@@ -1,4 +1,4 @@
-import { setPageFiles } from '../../shared/getPageFiles.js'
+import { setPageFiles } from '../../shared/getPageFiles'
 // @ts-ignore
 import * as pageFilesExports from 'virtual:vike:importUserCode:client:client-routing'
 setPageFiles(pageFilesExports)
diff --git a/vike/client/client-routing-runtime/prefetch.ts b/vike/client/client-routing-runtime/prefetch.ts
index b683d99e1f..472c175689 100644
--- a/vike/client/client-routing-runtime/prefetch.ts
+++ b/vike/client/client-routing-runtime/prefetch.ts
@@ -15,29 +15,29 @@ import {
   getGlobalObject,
   hasProp,
   objectAssign
-} from './utils.js'
+} from './utils'
 import {
   type PageContextUserFiles,
   isErrorFetchingStaticAssets,
   loadUserFilesClientSide
-} from '../shared/loadUserFilesClientSide.js'
-import { skipLink } from './skipLink.js'
-import { disableClientRouting } from './renderPageClientSide.js'
-import { isClientSideRoutable } from './isClientSideRoutable.js'
-import { createPageContext } from './createPageContext.js'
-import { route, type PageContextFromRoute } from '../../shared/route/index.js'
-import { noRouteMatch } from '../../shared/route/noRouteMatch.js'
-import { type PageContextFromServerHooks, getPageContextFromServerHooks } from './getPageContextFromHooks.js'
-import type { PageContextExports, PageFile } from '../../shared/getPageFiles.js'
-import { type PageConfigRuntime } from '../../shared/page-configs/PageConfig.js'
-import { getPageContextCurrent } from './getPageContextCurrent.js'
+} from '../shared/loadUserFilesClientSide'
+import { skipLink } from './skipLink'
+import { disableClientRouting } from './renderPageClientSide'
+import { isClientSideRoutable } from './isClientSideRoutable'
+import { createPageContext } from './createPageContext'
+import { route, type PageContextFromRoute } from '../../shared/route/index'
+import { noRouteMatch } from '../../shared/route/noRouteMatch'
+import { type PageContextFromServerHooks, getPageContextFromServerHooks } from './getPageContextFromHooks'
+import type { PageContextExports, PageFile } from '../../shared/getPageFiles'
+import { type PageConfigRuntime } from '../../shared/page-configs/PageConfig'
+import { getPageContextCurrent } from './getPageContextCurrent'
 import {
   PAGE_CONTEXT_MAX_AGE_DEFAULT,
   type PrefetchSettingResolved,
   getPrefetchSettings
-} from './prefetch/getPrefetchSettings.js'
+} from './prefetch/getPrefetchSettings'
 import pc from '@brillout/picocolors'
-import { normalizeUrlArgument } from './normalizeUrlArgument.js'
+import { normalizeUrlArgument } from './normalizeUrlArgument'
 
 assertClientRouting()
 const globalObject = getGlobalObject('prefetch.ts', {
diff --git a/vike/client/client-routing-runtime/prefetch/getPrefetchSettings.ts b/vike/client/client-routing-runtime/prefetch/getPrefetchSettings.ts
index 7066fac88e..a325640d38 100644
--- a/vike/client/client-routing-runtime/prefetch/getPrefetchSettings.ts
+++ b/vike/client/client-routing-runtime/prefetch/getPrefetchSettings.ts
@@ -4,9 +4,9 @@ export { getPrefetchSettings }
 export { PAGE_CONTEXT_MAX_AGE_DEFAULT }
 export type { PrefetchSettingResolved }
 
-import { assertUsage, assertInfo } from '../utils.js'
-import type { PageContextExports } from '../../../shared/getPageFiles.js'
-import type { PrefetchSetting, PrefetchStaticAssets } from './PrefetchSetting.js'
+import { assertUsage, assertInfo } from '../utils'
+import type { PageContextExports } from '../../../shared/getPageFiles'
+import type { PrefetchSetting, PrefetchStaticAssets } from './PrefetchSetting'
 
 // TODO/pageContext-prefetch: Make it `Infinity` for pre-rendered pages.
 const PAGE_CONTEXT_MAX_AGE_DEFAULT = 5000
diff --git a/vike/client/client-routing-runtime/renderPageClientSide.ts b/vike/client/client-routing-runtime/renderPageClientSide.ts
index d6caa4da23..15b52f036e 100644
--- a/vike/client/client-routing-runtime/renderPageClientSide.ts
+++ b/vike/client/client-routing-runtime/renderPageClientSide.ts
@@ -15,7 +15,7 @@ import {
   augmentType,
   genPromise,
   isCallable
-} from './utils.js'
+} from './utils'
 import {
   getPageContextFromClientHooks,
   getPageContextFromServerHooks,
@@ -24,35 +24,35 @@ import {
   type PageContextFromServerHooks,
   setPageContextInitIsPassedToClient,
   PageContextFromClientHooks
-} from './getPageContextFromHooks.js'
-import { createPageContext } from './createPageContext.js'
+} from './getPageContextFromHooks'
+import { createPageContext } from './createPageContext'
 import {
   addLinkPrefetchHandlers,
   addLinkPrefetchHandlers_unwatch,
   addLinkPrefetchHandlers_watch,
   getPageContextPrefetched,
   populatePageContextPrefetchCache
-} from './prefetch.js'
-import { assertInfo, assertWarning, isReact } from './utils.js'
-import { type PageContextBeforeRenderClient, executeOnRenderClientHook } from '../shared/executeOnRenderClientHook.js'
-import { assertHook, getHook } from '../../shared/hooks/getHook.js'
-import { isErrorFetchingStaticAssets, loadUserFilesClientSide } from '../shared/loadUserFilesClientSide.js'
-import { pushHistoryState } from './history.js'
+} from './prefetch'
+import { assertInfo, assertWarning, isReact } from './utils'
+import { type PageContextBeforeRenderClient, executeOnRenderClientHook } from '../shared/executeOnRenderClientHook'
+import { assertHook, getHook } from '../../shared/hooks/getHook'
+import { isErrorFetchingStaticAssets, loadUserFilesClientSide } from '../shared/loadUserFilesClientSide'
+import { pushHistoryState } from './history'
 import {
   assertNoInfiniteAbortLoop,
   getPageContextFromAllRewrites,
   isAbortError,
   logAbortErrorHandled,
   type PageContextFromRewrite
-} from '../../shared/route/abort.js'
-import { route } from '../../shared/route/index.js'
-import { isClientSideRoutable } from './isClientSideRoutable.js'
-import { setScrollPosition, type ScrollTarget } from './setScrollPosition.js'
-import { browserNativeScrollRestoration_disable, setInitialRenderIsDone } from './scrollRestoration.js'
-import { getErrorPageId } from '../../shared/error-page.js'
-import type { PageContextExports } from '../../shared/getPageFiles.js'
-import { setPageContextCurrent } from './getPageContextCurrent.js'
-import { getRouteStringParameterList } from '../../shared/route/resolveRouteString.js'
+} from '../../shared/route/abort'
+import { route } from '../../shared/route/index'
+import { isClientSideRoutable } from './isClientSideRoutable'
+import { setScrollPosition, type ScrollTarget } from './setScrollPosition'
+import { browserNativeScrollRestoration_disable, setInitialRenderIsDone } from './scrollRestoration'
+import { getErrorPageId } from '../../shared/error-page'
+import type { PageContextExports } from '../../shared/getPageFiles'
+import { setPageContextCurrent } from './getPageContextCurrent'
+import { getRouteStringParameterList } from '../../shared/route/resolveRouteString'
 
 const globalObject = getGlobalObject<{
   clientRoutingIsDisabled?: true
diff --git a/vike/client/client-routing-runtime/scrollRestoration.ts b/vike/client/client-routing-runtime/scrollRestoration.ts
index 9219cad691..8c7ae669c1 100644
--- a/vike/client/client-routing-runtime/scrollRestoration.ts
+++ b/vike/client/client-routing-runtime/scrollRestoration.ts
@@ -4,7 +4,7 @@ export { browserNativeScrollRestoration_disable }
 export { setupNativeScrollRestoration }
 export { setInitialRenderIsDone }
 
-import { getGlobalObject, onPageHide, onPageShow } from './utils.js'
+import { getGlobalObject, onPageHide, onPageShow } from './utils'
 const globalObject = getGlobalObject<{
   initialRenderIsDone?: true
 }>('scrollRestoration.ts', {})
diff --git a/vike/client/client-routing-runtime/setScrollPosition.ts b/vike/client/client-routing-runtime/setScrollPosition.ts
index 6c8e45e772..aaf024eb5e 100644
--- a/vike/client/client-routing-runtime/setScrollPosition.ts
+++ b/vike/client/client-routing-runtime/setScrollPosition.ts
@@ -2,8 +2,8 @@ export { setScrollPosition }
 export { autoSaveScrollPosition }
 export type { ScrollTarget }
 
-import { assert, onPageHide, sleep, throttle } from './utils.js'
-import { saveScrollPosition, type ScrollPosition } from './history.js'
+import { assert, onPageHide, sleep, throttle } from './utils'
+import { saveScrollPosition, type ScrollPosition } from './history'
 
 type ScrollTarget = undefined | { preserveScroll: boolean } | ScrollPosition
 function setScrollPosition(scrollTarget: ScrollTarget): void {
diff --git a/vike/client/client-routing-runtime/skipLink.ts b/vike/client/client-routing-runtime/skipLink.ts
index 3265798c18..981ac00810 100644
--- a/vike/client/client-routing-runtime/skipLink.ts
+++ b/vike/client/client-routing-runtime/skipLink.ts
@@ -1,7 +1,7 @@
 export { skipLink }
 
-import { getBaseServer } from './getBaseServer.js'
-import { assert, parseUrl, isBaseServer, isUrl, isUrlExternal } from './utils.js'
+import { getBaseServer } from './getBaseServer'
+import { assert, parseUrl, isBaseServer, isUrl, isUrlExternal } from './utils'
 
 function skipLink(linkTag: HTMLElement): boolean {
   const url = linkTag.getAttribute('href')
diff --git a/vike/client/client-routing-runtime/utils.ts b/vike/client/client-routing-runtime/utils.ts
index 7b1db9a9ab..7315f0b6b5 100644
--- a/vike/client/client-routing-runtime/utils.ts
+++ b/vike/client/client-routing-runtime/utils.ts
@@ -1,34 +1,34 @@
 // Utils needed by Client Routing.
 
 // We assume all runtime entries will load this utils.ts file
-import { onLoad } from './onLoad.js'
+import { onLoad } from './onLoad'
 onLoad()
 
 // We load the Server Routing utils: we tolerate the tiny amount of code that is only needed by Server Routing (only 1-2 lines).
 // We re-export some of the utils down below only to list the utils needed by Client Routing.
-export * from '../server-routing-runtime/utils.js'
+export * from '../server-routing-runtime/utils'
 
-export * from '../../utils/assert.js'
-export * from '../../utils/assertSingleInstance.js'
-export * from '../../shared/hooks/executeHook.js'
-export * from '../../utils/getCurrentUrl.js'
-export * from '../../utils/getGlobalObject.js'
-export * from '../../utils/hasProp.js'
-export * from '../../utils/isBrowser.js'
-export * from '../../utils/isCallable.js'
-export * from '../../utils/isObject.js'
-export * from '../../utils/isPlainObject.js'
-export * from '../../utils/isReact.js'
-export * from '../../utils/isSameErrorMessage.js'
-export * from '../../utils/objectAssign.js'
-export * from '../../utils/parseUrl.js'
-export * from '../../utils/PromiseType.js'
-export * from '../../utils/redirectHard.js'
-export * from '../../utils/sleep.js'
-export * from '../../utils/slice.js'
-export * from '../../utils/throttle.js'
-export * from '../../utils/assertRoutingType.js'
-export * from '../../utils/onPageVisibilityChange.js'
-export * from '../../utils/augmentType.js'
-export * from '../../utils/PROJECT_VERSION.js'
-export * from '../../utils/genPromise.js'
+export * from '../../utils/assert'
+export * from '../../utils/assertSingleInstance'
+export * from '../../shared/hooks/executeHook'
+export * from '../../utils/getCurrentUrl'
+export * from '../../utils/getGlobalObject'
+export * from '../../utils/hasProp'
+export * from '../../utils/isBrowser'
+export * from '../../utils/isCallable'
+export * from '../../utils/isObject'
+export * from '../../utils/isPlainObject'
+export * from '../../utils/isReact'
+export * from '../../utils/isSameErrorMessage'
+export * from '../../utils/objectAssign'
+export * from '../../utils/parseUrl'
+export * from '../../utils/PromiseType'
+export * from '../../utils/redirectHard'
+export * from '../../utils/sleep'
+export * from '../../utils/slice'
+export * from '../../utils/throttle'
+export * from '../../utils/assertRoutingType'
+export * from '../../utils/onPageVisibilityChange'
+export * from '../../utils/augmentType'
+export * from '../../utils/PROJECT_VERSION'
+export * from '../../utils/genPromise'
diff --git a/vike/client/node.ts b/vike/client/node.ts
index 16cd89ad6a..74bd294b77 100644
--- a/vike/client/node.ts
+++ b/vike/client/node.ts
@@ -1,4 +1,4 @@
-import { assertUsage } from './server-routing-runtime/utils.js'
+import { assertUsage } from './server-routing-runtime/utils'
 assertUsage(
   false,
   [
diff --git a/vike/client/server-routing-runtime/entry.ts b/vike/client/server-routing-runtime/entry.ts
index 43709ac8fc..cc73605bf2 100644
--- a/vike/client/server-routing-runtime/entry.ts
+++ b/vike/client/server-routing-runtime/entry.ts
@@ -1,12 +1,12 @@
-import { assertServerRouting } from '../../utils/assertRoutingType.js'
+import { assertServerRouting } from '../../utils/assertRoutingType'
 assertServerRouting()
 
 import './pageFiles'
-import { getPageContext } from './getPageContext.js'
-import { executeOnRenderClientHook } from '../shared/executeOnRenderClientHook.js'
-import { assertHook } from '../../shared/hooks/getHook.js'
-import { assertSingleInstance_onClientEntryServerRouting } from './utils.js'
-import { removeFoucBuster } from '../shared/removeFoucBuster.js'
+import { getPageContext } from './getPageContext'
+import { executeOnRenderClientHook } from '../shared/executeOnRenderClientHook'
+import { assertHook } from '../../shared/hooks/getHook'
+import { assertSingleInstance_onClientEntryServerRouting } from './utils'
+import { removeFoucBuster } from '../shared/removeFoucBuster'
 // @ts-ignore Since dist/cjs/client/ is never used, we can ignore this error.
 const isProd: boolean = import.meta.env.PROD
 assertSingleInstance_onClientEntryServerRouting(isProd)
diff --git a/vike/client/server-routing-runtime/getPageContext.ts b/vike/client/server-routing-runtime/getPageContext.ts
index 025c15cb74..1085589ced 100644
--- a/vike/client/server-routing-runtime/getPageContext.ts
+++ b/vike/client/server-routing-runtime/getPageContext.ts
@@ -1,7 +1,7 @@
-import { assertUsage, assertWarning, getCurrentUrl, objectAssign } from './utils.js'
-import { getPageContextSerializedInHtml } from '../shared/getPageContextSerializedInHtml.js'
-import { getPageFilesAll } from '../../shared/getPageFiles.js'
-import { loadUserFilesClientSide } from '../shared/loadUserFilesClientSide.js'
+import { assertUsage, assertWarning, getCurrentUrl, objectAssign } from './utils'
+import { getPageContextSerializedInHtml } from '../shared/getPageContextSerializedInHtml'
+import { getPageFilesAll } from '../../shared/getPageFiles'
+import { loadUserFilesClientSide } from '../shared/loadUserFilesClientSide'
 
 export { getPageContext }
 
diff --git a/vike/client/server-routing-runtime/index.ts b/vike/client/server-routing-runtime/index.ts
index 60555f7fe1..5d99fee090 100644
--- a/vike/client/server-routing-runtime/index.ts
+++ b/vike/client/server-routing-runtime/index.ts
@@ -1,6 +1,6 @@
 // TODO/v1-release: remove this file
 
-import type { PageContextBuiltInClientWithServerRouting } from '../../shared/types.js'
+import type { PageContextBuiltInClientWithServerRouting } from '../../shared/types'
 /** @deprecated
  * Replace:
  *   ```
diff --git a/vike/client/server-routing-runtime/onLoad.ts b/vike/client/server-routing-runtime/onLoad.ts
index 4177544f14..b8aad18cad 100644
--- a/vike/client/server-routing-runtime/onLoad.ts
+++ b/vike/client/server-routing-runtime/onLoad.ts
@@ -1,6 +1,6 @@
 export { onLoad }
 
-import { assertIsBrowser } from '../../utils/assertIsBrowser.js'
+import { assertIsBrowser } from '../../utils/assertIsBrowser'
 
 function onLoad() {
   assertIsBrowser()
diff --git a/vike/client/server-routing-runtime/pageFiles.ts b/vike/client/server-routing-runtime/pageFiles.ts
index cd85aa52ad..835f842c3b 100644
--- a/vike/client/server-routing-runtime/pageFiles.ts
+++ b/vike/client/server-routing-runtime/pageFiles.ts
@@ -1,4 +1,4 @@
-import { setPageFiles } from '../../shared/getPageFiles.js'
+import { setPageFiles } from '../../shared/getPageFiles'
 // @ts-ignore
 import * as pageFilesExports from 'virtual:vike:importUserCode:client:server-routing'
 setPageFiles(pageFilesExports)
diff --git a/vike/client/server-routing-runtime/utils.ts b/vike/client/server-routing-runtime/utils.ts
index 8ab95bcc2f..25231c7c0d 100644
--- a/vike/client/server-routing-runtime/utils.ts
+++ b/vike/client/server-routing-runtime/utils.ts
@@ -1,20 +1,20 @@
 // Utils needed by Server Routing.
 
 // We assume all runtime entries will load this utils.ts file
-import { onLoad } from './onLoad.js'
+import { onLoad } from './onLoad'
 onLoad()
 
-export * from '../../utils/assert.js'
-export * from '../../utils/assertSingleInstance.js'
-export * from '../../shared/hooks/executeHook.js'
-export * from '../../utils/checkType.js' // Only used by Server Routing (not needed for Client Routing)
-export * from '../../utils/getCurrentUrl.js'
-export * from '../../utils/getGlobalObject.js'
-export * from '../../utils/hasProp.js'
-export * from '../../utils/isCallable.js'
-export * from '../../utils/isObject.js'
-export * from '../../utils/objectAssign.js'
-export * from '../../utils/parseUrl.js'
-export * from '../../utils/slice.js'
-export * from '../../utils/unique.js' // Only used by Server Routing (not needed for Client Routing)
-export * from '../../utils/getPropAccessNotation.js'
+export * from '../../utils/assert'
+export * from '../../utils/assertSingleInstance'
+export * from '../../shared/hooks/executeHook'
+export * from '../../utils/checkType' // Only used by Server Routing (not needed for Client Routing)
+export * from '../../utils/getCurrentUrl'
+export * from '../../utils/getGlobalObject'
+export * from '../../utils/hasProp'
+export * from '../../utils/isCallable'
+export * from '../../utils/isObject'
+export * from '../../utils/objectAssign'
+export * from '../../utils/parseUrl'
+export * from '../../utils/slice'
+export * from '../../utils/unique' // Only used by Server Routing (not needed for Client Routing)
+export * from '../../utils/getPropAccessNotation'
diff --git a/vike/client/shared/executeOnRenderClientHook.ts b/vike/client/shared/executeOnRenderClientHook.ts
index 2e8838b023..979cbe5189 100644
--- a/vike/client/shared/executeOnRenderClientHook.ts
+++ b/vike/client/shared/executeOnRenderClientHook.ts
@@ -1,14 +1,14 @@
 export { executeOnRenderClientHook }
 export type { PageContextBeforeRenderClient }
 
-import { assert, assertUsage, executeHook } from '../server-routing-runtime/utils.js'
-import { getHook, type Hook } from '../../shared/hooks/getHook.js'
-import type { PageFile, PageContextExports } from '../../shared/getPageFiles.js'
+import { assert, assertUsage, executeHook } from '../server-routing-runtime/utils'
+import { getHook, type Hook } from '../../shared/hooks/getHook'
+import type { PageFile, PageContextExports } from '../../shared/getPageFiles'
 import {
   type PageContextForUserConsumptionClientSide,
   preparePageContextForUserConsumptionClientSide
-} from './preparePageContextForUserConsumptionClientSide.js'
-import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig.js'
+} from './preparePageContextForUserConsumptionClientSide'
+import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig'
 
 type PageContextBeforeRenderClient = {
   _pageFilesLoaded: PageFile[]
diff --git a/vike/client/shared/getPageContextProxyForUser.ts b/vike/client/shared/getPageContextProxyForUser.ts
index 6cbddff2d4..b8c90c6103 100644
--- a/vike/client/shared/getPageContextProxyForUser.ts
+++ b/vike/client/shared/getPageContextProxyForUser.ts
@@ -7,8 +7,8 @@ import {
   assertWarning,
   getGlobalObject,
   getPropAccessNotation
-} from '../server-routing-runtime/utils.js'
-import { notSerializable } from '../../shared/notSerializable.js'
+} from '../server-routing-runtime/utils'
+import { notSerializable } from '../../shared/notSerializable'
 const globalObject = getGlobalObject<{ prev?: string }>('getPageContextProxyForUser.ts', {})
 
 type PageContextForPassToClientWarning = {
diff --git a/vike/client/shared/getPageContextSerializedInHtml.ts b/vike/client/shared/getPageContextSerializedInHtml.ts
index f1ed3158d5..8f6602cdba 100644
--- a/vike/client/shared/getPageContextSerializedInHtml.ts
+++ b/vike/client/shared/getPageContextSerializedInHtml.ts
@@ -1,5 +1,5 @@
 import { parse } from '@brillout/json-serializer/parse'
-import { hasProp, assert, assertUsage } from '../server-routing-runtime/utils.js'
+import { hasProp, assert, assertUsage } from '../server-routing-runtime/utils'
 
 export { getPageContextSerializedInHtml }
 
diff --git a/vike/client/shared/loadUserFilesClientSide.ts b/vike/client/shared/loadUserFilesClientSide.ts
index 61da203a19..ce125fe493 100644
--- a/vike/client/shared/loadUserFilesClientSide.ts
+++ b/vike/client/shared/loadUserFilesClientSide.ts
@@ -7,11 +7,11 @@ import {
   getPageContextExports,
   type PageFile,
   type PageContextExports
-} from '../../shared/getPageFiles.js'
-import { findPageConfig } from '../../shared/page-configs/findPageConfig.js'
-import { loadConfigValues } from '../../shared/page-configs/loadConfigValues.js'
-import type { PageConfigRuntime, PageConfigRuntimeLoaded } from '../../shared/page-configs/PageConfig.js'
-import { objectAssign } from '../server-routing-runtime/utils.js'
+} from '../../shared/getPageFiles'
+import { findPageConfig } from '../../shared/page-configs/findPageConfig'
+import { loadConfigValues } from '../../shared/page-configs/loadConfigValues'
+import type { PageConfigRuntime, PageConfigRuntimeLoaded } from '../../shared/page-configs/PageConfig'
+import { objectAssign } from '../server-routing-runtime/utils'
 
 const stamp = '__whileFetchingAssets'
 
diff --git a/vike/client/shared/preparePageContextForUserConsumptionClientSide.ts b/vike/client/shared/preparePageContextForUserConsumptionClientSide.ts
index c4d8aeb981..12bd4d565f 100644
--- a/vike/client/shared/preparePageContextForUserConsumptionClientSide.ts
+++ b/vike/client/shared/preparePageContextForUserConsumptionClientSide.ts
@@ -1,12 +1,12 @@
 export { preparePageContextForUserConsumptionClientSide }
 export type { PageContextForUserConsumptionClientSide }
 
-import { assert, objectAssign } from '../server-routing-runtime/utils.js'
-import type { PageContextExports } from '../../shared/getPageFiles.js'
-import type { PageContextClient, PageContextClientWithServerRouting } from '../../shared/types.js'
-import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig.js'
-import { getPageContextProxyForUser, PageContextForPassToClientWarning } from './getPageContextProxyForUser.js'
-import { preparePageContextForUserConsumption } from '../../shared/preparePageContextForUserConsumption.js'
+import { assert, objectAssign } from '../server-routing-runtime/utils'
+import type { PageContextExports } from '../../shared/getPageFiles'
+import type { PageContextClient, PageContextClientWithServerRouting } from '../../shared/types'
+import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig'
+import { getPageContextProxyForUser, PageContextForPassToClientWarning } from './getPageContextProxyForUser'
+import { preparePageContextForUserConsumption } from '../../shared/preparePageContextForUserConsumption'
 
 type PageContextForUserConsumptionClientSide = PageContextExports &
   PageContextForPassToClientWarning & {
diff --git a/vike/client/shared/removeFoucBuster.ts b/vike/client/shared/removeFoucBuster.ts
index d89399a719..796ce3b55d 100644
--- a/vike/client/shared/removeFoucBuster.ts
+++ b/vike/client/shared/removeFoucBuster.ts
@@ -1,6 +1,6 @@
 export { removeFoucBuster }
 
-import { assert } from './utils.js'
+import { assert } from './utils'
 
 // See also:
 // - Alternative approach of exactly injecting what Vite injects:
diff --git a/vike/client/shared/utils.ts b/vike/client/shared/utils.ts
index abf1292b48..41df7afb97 100644
--- a/vike/client/shared/utils.ts
+++ b/vike/client/shared/utils.ts
@@ -1 +1 @@
-export * from '../../utils/assert.js'
+export * from '../../utils/assert'
diff --git a/vike/node/cli/bin-entry.js b/vike/node/cli/bin-entry.js
index 85018024cf..8fa9b80be6 100755
--- a/vike/node/cli/bin-entry.js
+++ b/vike/node/cli/bin-entry.js
@@ -1,3 +1,3 @@
 #!/usr/bin/env node
 
-import '../../dist/esm/node/cli/bin.js'
+import '../../dist/esm/node/cli/bin'
diff --git a/vike/node/cli/bin.ts b/vike/node/cli/bin.ts
index f378af4ffc..42c335e3fb 100644
--- a/vike/node/cli/bin.ts
+++ b/vike/node/cli/bin.ts
@@ -1,7 +1,7 @@
 import { cac } from 'cac'
 import { resolve } from 'path'
-import { runPrerenderFromCLI, runPrerender_forceExit } from '../prerender/runPrerender.js'
-import { projectInfo, assertUsage, assertWarning } from './utils.js'
+import { runPrerenderFromCLI, runPrerender_forceExit } from '../prerender/runPrerender'
+import { projectInfo, assertUsage, assertWarning } from './utils'
 import pc from '@brillout/picocolors'
 
 const cli = cac(projectInfo.projectName)
diff --git a/vike/node/cli/index.ts b/vike/node/cli/index.ts
index 006a344b8b..150c3577dc 100644
--- a/vike/node/cli/index.ts
+++ b/vike/node/cli/index.ts
@@ -1,7 +1,7 @@
 // TODO/v1-release: remove this file
 
-import { prerender as prerenderOriginal } from '../prerender/index.js'
-import { assertWarning } from './utils.js'
+import { prerender as prerenderOriginal } from '../prerender/index'
+import { assertWarning } from './utils'
 export const prerender: typeof prerenderOriginal = (options) => {
   assertWarning(
     false,
diff --git a/vike/node/cli/onLoad.ts b/vike/node/cli/onLoad.ts
index 9b3d350cd1..53e18b9dfc 100644
--- a/vike/node/cli/onLoad.ts
+++ b/vike/node/cli/onLoad.ts
@@ -1,6 +1,6 @@
 export { onLoad }
 
-import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser.js'
+import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser'
 
 function onLoad() {
   assertIsNotBrowser()
diff --git a/vike/node/cli/utils.ts b/vike/node/cli/utils.ts
index 3cdc0082e1..8d770d7c8f 100644
--- a/vike/node/cli/utils.ts
+++ b/vike/node/cli/utils.ts
@@ -1,6 +1,6 @@
 // We assume all runtime entries will load this utils.ts file
-import { onLoad } from './onLoad.js'
+import { onLoad } from './onLoad'
 onLoad()
 
-export * from '../../utils/assert.js'
-export * from '../../utils/projectInfo.js'
+export * from '../../utils/assert'
+export * from '../../utils/projectInfo'
diff --git a/vike/node/client/router.ts b/vike/node/client/router.ts
index bb310e5f4e..a2a6796fca 100644
--- a/vike/node/client/router.ts
+++ b/vike/node/client/router.ts
@@ -3,7 +3,7 @@ export { reload }
 export { prefetch }
 export { onPopState }
 
-import { assertWarning } from '../../utils/assert.js'
+import { assertWarning } from '../../utils/assert'
 
 // `never` to ensure package.json#exports["./client/router"].types points to type defined by the client-side code
 const navigate: never = (() => warnNoEffect('navigate')) as never
diff --git a/vike/node/createPageRenderer.ts b/vike/node/createPageRenderer.ts
index 2212521316..2790e090d8 100644
--- a/vike/node/createPageRenderer.ts
+++ b/vike/node/createPageRenderer.ts
@@ -1,9 +1,9 @@
 // TODO/v1-release: remove this file
 
-//import { SsrEnv, setSsrEnv } from './ssrEnv.js'
-import { renderPage } from './runtime/renderPage.js'
-import { assertWarning } from './runtime/utils.js'
-//import { importBuildWasLoaded } from './importBuild.js'
+//import { SsrEnv, setSsrEnv } from './ssrEnv'
+import { renderPage } from './runtime/renderPage'
+import { assertWarning } from './runtime/utils'
+//import { importBuildWasLoaded } from './importBuild'
 
 export { createPageRenderer }
 
diff --git a/vike/node/plugin/index.ts b/vike/node/plugin/index.ts
index 6ce52b69fe..a6f92a016b 100644
--- a/vike/node/plugin/index.ts
+++ b/vike/node/plugin/index.ts
@@ -3,33 +3,33 @@ export { plugin }
 // TODO/v1-release: remove
 export { plugin as ssr }
 export type { ConfigVikeUserProvided as UserConfig }
-export { PROJECT_VERSION as version } from './utils.js'
+export { PROJECT_VERSION as version } from './utils'
 
 import { version, type Plugin } from 'vite'
-import { assertNodeEnv_onVikePluginLoad, assertUsage, assertVersion, markEnvAsVikePluginLoaded } from './utils.js'
-import { buildConfig } from './plugins/buildConfig.js'
-import { previewConfig } from './plugins/previewConfig.js'
-import { autoFullBuild } from './plugins/autoFullBuild.js'
-import { devConfig } from './plugins/devConfig/index.js'
-import { packageJsonFile } from './plugins/packageJsonFile.js'
-import { removeRequireHookPlugin } from './plugins/removeRequireHookPlugin.js'
-import { importUserCode } from './plugins/importUserCode/index.js'
-import { resolveVikeConfig } from './plugins/config/index.js'
-import type { ConfigVikeUserProvided } from '../../shared/ConfigVike.js'
-import { distFileNames } from './plugins/distFileNames.js'
-import { extractAssetsPlugin } from './plugins/extractAssetsPlugin.js'
-import { extractExportNamesPlugin } from './plugins/extractExportNamesPlugin.js'
-import { suppressRollupWarning } from './plugins/suppressRollupWarning.js'
-import { setGlobalContext } from './plugins/setGlobalContext.js'
-import { importBuild } from './plugins/importBuild/index.js'
-import { commonConfig } from './plugins/commonConfig.js'
-import { baseUrls } from './plugins/baseUrls.js'
-import { envVarsPlugin } from './plugins/envVars.js'
+import { assertNodeEnv_onVikePluginLoad, assertUsage, assertVersion, markEnvAsVikePluginLoaded } from './utils'
+import { buildConfig } from './plugins/buildConfig'
+import { previewConfig } from './plugins/previewConfig'
+import { autoFullBuild } from './plugins/autoFullBuild'
+import { devConfig } from './plugins/devConfig/index'
+import { packageJsonFile } from './plugins/packageJsonFile'
+import { removeRequireHookPlugin } from './plugins/removeRequireHookPlugin'
+import { importUserCode } from './plugins/importUserCode/index'
+import { resolveVikeConfig } from './plugins/config/index'
+import type { ConfigVikeUserProvided } from '../../shared/ConfigVike'
+import { distFileNames } from './plugins/distFileNames'
+import { extractAssetsPlugin } from './plugins/extractAssetsPlugin'
+import { extractExportNamesPlugin } from './plugins/extractExportNamesPlugin'
+import { suppressRollupWarning } from './plugins/suppressRollupWarning'
+import { setGlobalContext } from './plugins/setGlobalContext'
+import { importBuild } from './plugins/importBuild/index'
+import { commonConfig } from './plugins/commonConfig'
+import { baseUrls } from './plugins/baseUrls'
+import { envVarsPlugin } from './plugins/envVars'
 import pc from '@brillout/picocolors'
-import { fileEnv } from './plugins/fileEnv.js'
-import { setResolveClientEntriesDev } from '../runtime/renderPage/getPageAssets.js'
-import { resolveClientEntriesDev } from './resolveClientEntriesDev.js'
-import { workaroundCssModuleHmr } from './plugins/workaroundCssModuleHmr.js'
+import { fileEnv } from './plugins/fileEnv'
+import { setResolveClientEntriesDev } from '../runtime/renderPage/getPageAssets'
+import { resolveClientEntriesDev } from './resolveClientEntriesDev'
+import { workaroundCssModuleHmr } from './plugins/workaroundCssModuleHmr'
 
 assertNodeEnv_onVikePluginLoad()
 markEnvAsVikePluginLoaded()
diff --git a/vike/node/plugin/onLoad.ts b/vike/node/plugin/onLoad.ts
index ba4d541323..2c7e64a0ed 100644
--- a/vike/node/plugin/onLoad.ts
+++ b/vike/node/plugin/onLoad.ts
@@ -1,8 +1,8 @@
 export { onLoad }
 
-import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser.js'
-import { assertIsNotProductionRuntime } from '../../utils/assertIsNotProductionRuntime.js'
-import { assertNodeVersion } from '../../utils/assertNodeVersion.js'
+import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser'
+import { assertIsNotProductionRuntime } from '../../utils/assertIsNotProductionRuntime'
+import { assertNodeVersion } from '../../utils/assertNodeVersion'
 
 function onLoad() {
   assertIsNotBrowser()
diff --git a/vike/node/plugin/plugins/autoFullBuild.ts b/vike/node/plugin/plugins/autoFullBuild.ts
index ffd4d65634..812b161daf 100644
--- a/vike/node/plugin/plugins/autoFullBuild.ts
+++ b/vike/node/plugin/plugins/autoFullBuild.ts
@@ -2,14 +2,14 @@ export { autoFullBuild }
 
 import { build } from 'vite'
 import type { InlineConfig, Plugin, ResolvedConfig } from 'vite'
-import { assertWarning } from '../utils.js'
-import { runPrerenderFromAutoFullBuild, runPrerender_forceExit } from '../../prerender/runPrerender.js'
-import { getConfigVike } from '../../shared/getConfigVike.js'
-import type { ConfigVikeResolved } from '../../../shared/ConfigVike.js'
-import { isViteCliCall, getViteConfigFromCli } from '../shared/isViteCliCall.js'
+import { assertWarning } from '../utils'
+import { runPrerenderFromAutoFullBuild, runPrerender_forceExit } from '../../prerender/runPrerender'
+import { getConfigVike } from '../../shared/getConfigVike'
+import type { ConfigVikeResolved } from '../../../shared/ConfigVike'
+import { isViteCliCall, getViteConfigFromCli } from '../shared/isViteCliCall'
 import pc from '@brillout/picocolors'
-import { logErrorHint } from '../../runtime/renderPage/logErrorHint.js'
-import { manifestTempFile } from './buildConfig.js'
+import { logErrorHint } from '../../runtime/renderPage/logErrorHint'
+import { manifestTempFile } from './buildConfig'
 
 let forceExit = false
 
diff --git a/vike/node/plugin/plugins/baseUrls.ts b/vike/node/plugin/plugins/baseUrls.ts
index 1a5e364e99..482eb18268 100644
--- a/vike/node/plugin/plugins/baseUrls.ts
+++ b/vike/node/plugin/plugins/baseUrls.ts
@@ -1,10 +1,10 @@
 export { baseUrls }
 
 import type { Plugin } from 'vite'
-import { resolveBaseFromUserConfig } from '../plugins/config/resolveBase.js'
-import { assert } from '../utils.js'
-import { getConfigVike } from '../../shared/getConfigVike.js'
-import type { ConfigVikeUserProvided } from '../../../shared/ConfigVike.js'
+import { resolveBaseFromUserConfig } from '../plugins/config/resolveBase'
+import { assert } from '../utils'
+import { getConfigVike } from '../../shared/getConfigVike'
+import type { ConfigVikeUserProvided } from '../../../shared/ConfigVike'
 
 function baseUrls(configVike?: ConfigVikeUserProvided): Plugin {
   let baseServer: string
diff --git a/vike/node/plugin/plugins/buildConfig.ts b/vike/node/plugin/plugins/buildConfig.ts
index c1ef089dc9..34e8d8ddf8 100644
--- a/vike/node/plugin/plugins/buildConfig.ts
+++ b/vike/node/plugin/plugins/buildConfig.ts
@@ -17,23 +17,23 @@ import {
   type OutDirs,
   assertNodeEnv_build,
   assertIsNpmPackageImport
-} from '../utils.js'
-import { getVikeConfig, isV1Design } from './importUserCode/v1-design/getVikeConfig.js'
-import { findPageFiles } from '../shared/findPageFiles.js'
-import { getConfigVike } from '../../shared/getConfigVike.js'
+} from '../utils'
+import { getVikeConfig, isV1Design } from './importUserCode/v1-design/getVikeConfig'
+import { findPageFiles } from '../shared/findPageFiles'
+import { getConfigVike } from '../../shared/getConfigVike'
 import type { ResolvedConfig, Plugin, UserConfig } from 'vite'
-import { getVirtualFileIdPageConfigValuesAll } from '../../shared/virtual-files/virtualFilePageConfigValuesAll.js'
-import type { PageConfigBuildTime } from '../../../shared/page-configs/PageConfig.js'
-import type { FileType } from '../../../shared/getPageFiles/fileTypes.js'
-import { extractAssetsAddQuery } from '../../shared/extractAssetsQuery.js'
+import { getVirtualFileIdPageConfigValuesAll } from '../../shared/virtual-files/virtualFilePageConfigValuesAll'
+import type { PageConfigBuildTime } from '../../../shared/page-configs/PageConfig'
+import type { FileType } from '../../../shared/getPageFiles/fileTypes'
+import { extractAssetsAddQuery } from '../../shared/extractAssetsQuery'
 import { createRequire } from 'module'
 import fs from 'fs/promises'
 import path from 'path'
-import { fixServerAssets, fixServerAssets_isEnabled } from './buildConfig/fixServerAssets.js'
-import { set_ASSETS_MAP } from './importBuild/index.js'
-import { prependEntriesDir } from '../../shared/prependEntriesDir.js'
-import { getFilePathResolved } from '../shared/getFilePath.js'
-import { getConfigValueBuildTime } from '../../../shared/page-configs/getConfigValueBuildTime.js'
+import { fixServerAssets, fixServerAssets_isEnabled } from './buildConfig/fixServerAssets'
+import { set_ASSETS_MAP } from './importBuild/index'
+import { prependEntriesDir } from '../../shared/prependEntriesDir'
+import { getFilePathResolved } from '../shared/getFilePath'
+import { getConfigValueBuildTime } from '../../../shared/page-configs/getConfigValueBuildTime'
 // @ts-ignore Shimmed by dist-cjs-fixup.js for CJS build.
 const importMetaUrl: string = import.meta.url
 const require_ = createRequire(importMetaUrl)
diff --git a/vike/node/plugin/plugins/buildConfig/fixServerAssets.ts b/vike/node/plugin/plugins/buildConfig/fixServerAssets.ts
index 321b0041ce..f9cde15277 100644
--- a/vike/node/plugin/plugins/buildConfig/fixServerAssets.ts
+++ b/vike/node/plugin/plugins/buildConfig/fixServerAssets.ts
@@ -4,12 +4,12 @@ export { fixServerAssets_isEnabled }
 import fs from 'fs/promises'
 import path from 'path'
 import { existsSync } from 'fs'
-import { ViteManifest, ViteManifestEntry } from '../../../shared/ViteManifest.js'
-import { assert, getOutDirs, pLimit, unique } from '../../utils.js'
-import { isVirtualFileIdPageConfigValuesAll } from '../../../shared/virtual-files/virtualFilePageConfigValuesAll.js'
-import { manifestTempFile } from '../buildConfig.js'
+import { ViteManifest, ViteManifestEntry } from '../../../shared/ViteManifest'
+import { assert, getOutDirs, pLimit, unique } from '../../utils'
+import { isVirtualFileIdPageConfigValuesAll } from '../../../shared/virtual-files/virtualFilePageConfigValuesAll'
+import { manifestTempFile } from '../buildConfig'
 import { ResolvedConfig } from 'vite'
-import { getAssetsDir } from '../../shared/getAssetsDir.js'
+import { getAssetsDir } from '../../shared/getAssetsDir'
 
 /**
  * true  => use workaround config.build.ssrEmitAssets
diff --git a/vike/node/plugin/plugins/commonConfig.ts b/vike/node/plugin/plugins/commonConfig.ts
index cf910b281c..ec6a62a1a2 100644
--- a/vike/node/plugin/plugins/commonConfig.ts
+++ b/vike/node/plugin/plugins/commonConfig.ts
@@ -1,12 +1,12 @@
 export { commonConfig }
 
 import type { Plugin, ResolvedConfig } from 'vite'
-import { assert, assertUsage, assertWarning, findPackageJson } from '../utils.js'
-import { assertRollupInput } from './buildConfig.js'
+import { assert, assertUsage, assertWarning, findPackageJson } from '../utils'
+import { assertRollupInput } from './buildConfig'
 import { installRequireShim_setUserRootDir } from '@brillout/require-shim'
 import pc from '@brillout/picocolors'
 import path from 'path'
-import { assertResolveAlias } from './commonConfig/assertResolveAlias.js'
+import { assertResolveAlias } from './commonConfig/assertResolveAlias'
 const pluginName = 'vike:commonConfig-1'
 
 function commonConfig(): Plugin[] {
diff --git a/vike/node/plugin/plugins/commonConfig/assertResolveAlias.ts b/vike/node/plugin/plugins/commonConfig/assertResolveAlias.ts
index 62821f7f6d..277cb4401d 100644
--- a/vike/node/plugin/plugins/commonConfig/assertResolveAlias.ts
+++ b/vike/node/plugin/plugins/commonConfig/assertResolveAlias.ts
@@ -1,7 +1,7 @@
 export { assertResolveAlias }
 
 import type { ResolvedConfig } from 'vite'
-import { assert, assertUsage, assertWarning, isArray, isValidPathAlias } from '../../utils.js'
+import { assert, assertUsage, assertWarning, isArray, isValidPathAlias } from '../../utils'
 import pc from '@brillout/picocolors'
 
 // Recommend users to avoid un-distinguishable path aliases.
diff --git a/vike/node/plugin/plugins/config/assertVikeConfig.ts b/vike/node/plugin/plugins/config/assertVikeConfig.ts
index b1edd7b1cb..95f2bc71ad 100644
--- a/vike/node/plugin/plugins/config/assertVikeConfig.ts
+++ b/vike/node/plugin/plugins/config/assertVikeConfig.ts
@@ -1,7 +1,7 @@
 export { assertVikeConfig }
 
-import { assert, assertUsage, hasProp, isObject } from '../../utils.js'
-import type { ConfigVikeUserProvided } from '../../../../shared/ConfigVike.js'
+import { assert, assertUsage, hasProp, isObject } from '../../utils'
+import type { ConfigVikeUserProvided } from '../../../../shared/ConfigVike'
 
 type WrongUsage = { prop: string; errMsg: `should be a${string}` }
 
diff --git a/vike/node/plugin/plugins/config/index.ts b/vike/node/plugin/plugins/config/index.ts
index 502724e0ea..485f7fdda9 100644
--- a/vike/node/plugin/plugins/config/index.ts
+++ b/vike/node/plugin/plugins/config/index.ts
@@ -1,12 +1,12 @@
 export { resolveVikeConfig }
 
 import type { Plugin, ResolvedConfig } from 'vite'
-import type { ConfigVikeUserProvided, ConfigVikeResolved } from '../../../../shared/ConfigVike.js'
-import { assertVikeConfig } from './assertVikeConfig.js'
-import { isDev2 } from '../../utils.js'
-import { pickFirst } from './pickFirst.js'
-import { resolveBase } from './resolveBase.js'
-import { getVikeConfig } from '../importUserCode/v1-design/getVikeConfig.js'
+import type { ConfigVikeUserProvided, ConfigVikeResolved } from '../../../../shared/ConfigVike'
+import { assertVikeConfig } from './assertVikeConfig'
+import { isDev2 } from '../../utils'
+import { pickFirst } from './pickFirst'
+import { resolveBase } from './resolveBase'
+import { getVikeConfig } from '../importUserCode/v1-design/getVikeConfig'
 import pc from '@brillout/picocolors'
 
 function resolveVikeConfig(vikeConfig: unknown): Plugin {
diff --git a/vike/node/plugin/plugins/config/resolveBase.ts b/vike/node/plugin/plugins/config/resolveBase.ts
index 26eeb0b48e..91330a7fa3 100644
--- a/vike/node/plugin/plugins/config/resolveBase.ts
+++ b/vike/node/plugin/plugins/config/resolveBase.ts
@@ -1,10 +1,10 @@
 export { resolveBase }
 export { resolveBaseFromUserConfig }
 
-import { assert, assertUsage, isBaseServer, isBaseAssets } from '../../utils.js'
+import { assert, assertUsage, isBaseServer, isBaseAssets } from '../../utils'
 import type { ResolvedConfig, UserConfig } from 'vite'
-import type { ConfigVikeUserProvided } from '../../../../shared/ConfigVike.js'
-import { pickFirst } from './pickFirst.js'
+import type { ConfigVikeUserProvided } from '../../../../shared/ConfigVike'
+import { pickFirst } from './pickFirst'
 import pc from '@brillout/picocolors'
 
 type BaseServers = {
diff --git a/vike/node/plugin/plugins/devConfig/determineFsAllowList.ts b/vike/node/plugin/plugins/devConfig/determineFsAllowList.ts
index 26ef556ab3..e87a23e4cb 100644
--- a/vike/node/plugin/plugins/devConfig/determineFsAllowList.ts
+++ b/vike/node/plugin/plugins/devConfig/determineFsAllowList.ts
@@ -3,7 +3,7 @@ export { determineFsAllowList }
 import { searchForWorkspaceRoot } from 'vite'
 import type { ResolvedConfig } from 'vite'
 import path from 'path'
-import { assert } from '../../utils.js'
+import { assert } from '../../utils'
 import { createRequire } from 'module'
 import { dirname } from 'path'
 import { fileURLToPath } from 'url'
diff --git a/vike/node/plugin/plugins/devConfig/determineOptimizeDeps.ts b/vike/node/plugin/plugins/devConfig/determineOptimizeDeps.ts
index 0552140241..d6bfa153f2 100644
--- a/vike/node/plugin/plugins/devConfig/determineOptimizeDeps.ts
+++ b/vike/node/plugin/plugins/devConfig/determineOptimizeDeps.ts
@@ -1,16 +1,16 @@
 export { determineOptimizeDeps }
 
 import type { ResolvedConfig } from 'vite'
-import { findPageFiles } from '../../shared/findPageFiles.js'
-import { assert, assertIsNpmPackageImport, createDebugger, isArray, unique } from '../../utils.js'
-import { getVikeConfig } from '../importUserCode/v1-design/getVikeConfig.js'
-import { analyzeClientEntries } from '../buildConfig.js'
-import type { PageConfigBuildTime } from '../../../../shared/page-configs/PageConfig.js'
+import { findPageFiles } from '../../shared/findPageFiles'
+import { assert, assertIsNpmPackageImport, createDebugger, isArray, unique } from '../../utils'
+import { getVikeConfig } from '../importUserCode/v1-design/getVikeConfig'
+import { analyzeClientEntries } from '../buildConfig'
+import type { PageConfigBuildTime } from '../../../../shared/page-configs/PageConfig'
 import {
   virtualFileIdImportUserCodeClientCR,
   virtualFileIdImportUserCodeClientSR
-} from '../../../shared/virtual-files/virtualFileImportUserCode.js'
-import { getFilePathResolved } from '../../shared/getFilePath.js'
+} from '../../../shared/virtual-files/virtualFileImportUserCode'
+import { getFilePathResolved } from '../../shared/getFilePath'
 
 const debug = createDebugger('vike:optimizeDeps')
 
diff --git a/vike/node/plugin/plugins/devConfig/index.ts b/vike/node/plugin/plugins/devConfig/index.ts
index 4cad9970f4..ba6198f7dc 100644
--- a/vike/node/plugin/plugins/devConfig/index.ts
+++ b/vike/node/plugin/plugins/devConfig/index.ts
@@ -1,13 +1,13 @@
 export { devConfig }
 
 import type { Plugin, ResolvedConfig, UserConfig } from 'vite'
-import { determineOptimizeDeps } from './determineOptimizeDeps.js'
-import { determineFsAllowList } from './determineFsAllowList.js'
-import { addSsrMiddleware } from '../../shared/addSsrMiddleware.js'
-import { markEnvAsViteDev } from '../../utils.js'
-import { improveViteLogs } from '../../shared/loggerVite.js'
-import { isErrorDebug } from '../../../shared/isErrorDebug.js'
-import { installHttpRequestAsyncStore } from '../../shared/getHttpRequestAsyncStore.js'
+import { determineOptimizeDeps } from './determineOptimizeDeps'
+import { determineFsAllowList } from './determineFsAllowList'
+import { addSsrMiddleware } from '../../shared/addSsrMiddleware'
+import { markEnvAsViteDev } from '../../utils'
+import { improveViteLogs } from '../../shared/loggerVite'
+import { isErrorDebug } from '../../../shared/isErrorDebug'
+import { installHttpRequestAsyncStore } from '../../shared/getHttpRequestAsyncStore'
 
 if (isErrorDebug()) {
   Error.stackTraceLimit = Infinity
diff --git a/vike/node/plugin/plugins/distFileNames.ts b/vike/node/plugin/plugins/distFileNames.ts
index 4a0c586ae1..599212f286 100644
--- a/vike/node/plugin/plugins/distFileNames.ts
+++ b/vike/node/plugin/plugins/distFileNames.ts
@@ -4,12 +4,12 @@ export { distFileNames }
 //  - https://github.com/vikejs/vike/commit/11a4c49e5403aa7c37c8020c462b499425b41854
 //  - Blocker: https://github.com/rollup/rollup/issues/4724
 
-import { assertPosixPath, assert, assertUsage, isArray, isCallable } from '../utils.js'
+import { assertPosixPath, assert, assertUsage, isArray, isCallable } from '../utils'
 import path from 'path'
 import crypto from 'crypto'
 import type { Plugin, ResolvedConfig, Rollup } from 'vite'
-import { getAssetsDir } from '../shared/getAssetsDir.js'
-import { assertModuleId, getModuleFilePathAbsolute } from '../shared/getFilePath.js'
+import { getAssetsDir } from '../shared/getAssetsDir'
+import { assertModuleId, getModuleFilePathAbsolute } from '../shared/getFilePath'
 type PreRenderedChunk = Rollup.PreRenderedChunk
 type PreRenderedAsset = Rollup.PreRenderedAsset
 
diff --git a/vike/node/plugin/plugins/envVars.ts b/vike/node/plugin/plugins/envVars.ts
index dbef4dce65..6ba791cfc2 100644
--- a/vike/node/plugin/plugins/envVars.ts
+++ b/vike/node/plugin/plugins/envVars.ts
@@ -2,10 +2,10 @@ export { envVarsPlugin }
 
 import type { Plugin, ResolvedConfig } from 'vite'
 import { loadEnv } from 'vite'
-import { assert, assertPosixPath, assertUsage, assertWarning, escapeRegex, isArray, lowerFirst } from '../utils.js'
-import { sourceMapPassthrough } from '../shared/rollupSourceMap.js'
-import { getModuleFilePathAbsolute } from '../shared/getFilePath.js'
-import { normalizeId } from '../shared/normalizeId.js'
+import { assert, assertPosixPath, assertUsage, assertWarning, escapeRegex, isArray, lowerFirst } from '../utils'
+import { sourceMapPassthrough } from '../shared/rollupSourceMap'
+import { getModuleFilePathAbsolute } from '../shared/getFilePath'
+import { normalizeId } from '../shared/normalizeId'
 
 // TODO/enventually: (after we implemented vike.config.js)
 // - Make import.meta.env work inside +config.js
diff --git a/vike/node/plugin/plugins/extractAssetsPlugin.ts b/vike/node/plugin/plugins/extractAssetsPlugin.ts
index 9fb4aadc26..51456ff08a 100644
--- a/vike/node/plugin/plugins/extractAssetsPlugin.ts
+++ b/vike/node/plugin/plugins/extractAssetsPlugin.ts
@@ -21,19 +21,19 @@ import {
   isVirtualFileId,
   getVirtualFileId,
   assertUsage
-} from '../utils.js'
-import { extractAssetsAddQuery } from '../../shared/extractAssetsQuery.js'
-import { getConfigVike } from '../../shared/getConfigVike.js'
-import type { ConfigVikeResolved } from '../../../shared/ConfigVike.js'
-import { isAsset } from '../shared/isAsset.js'
-import { getImportStatements, type ImportStatement } from '../shared/parseEsModule.js'
-import { sourceMapRemove } from '../shared/rollupSourceMap.js'
+} from '../utils'
+import { extractAssetsAddQuery } from '../../shared/extractAssetsQuery'
+import { getConfigVike } from '../../shared/getConfigVike'
+import type { ConfigVikeResolved } from '../../../shared/ConfigVike'
+import { isAsset } from '../shared/isAsset'
+import { getImportStatements, type ImportStatement } from '../shared/parseEsModule'
+import { sourceMapRemove } from '../shared/rollupSourceMap'
 import type { Rollup } from 'vite'
 import pc from '@brillout/picocolors'
-import { fixServerAssets_isEnabled } from './buildConfig/fixServerAssets.js'
-import { getVikeConfig, isV1Design, type VikeConfigObject } from './importUserCode/v1-design/getVikeConfig.js'
-import { assertV1Design } from '../../shared/assertV1Design.js'
-import { normalizeId } from '../shared/normalizeId.js'
+import { fixServerAssets_isEnabled } from './buildConfig/fixServerAssets'
+import { getVikeConfig, isV1Design, type VikeConfigObject } from './importUserCode/v1-design/getVikeConfig'
+import { assertV1Design } from '../../shared/assertV1Design'
+import { normalizeId } from '../shared/normalizeId'
 type ResolvedId = Rollup.ResolvedId
 
 const extractAssetsRE = /(\?|&)extractAssets(?:&|$)/
diff --git a/vike/node/plugin/plugins/extractExportNamesPlugin.ts b/vike/node/plugin/plugins/extractExportNamesPlugin.ts
index 9569b206d7..cc5c0fb3af 100644
--- a/vike/node/plugin/plugins/extractExportNamesPlugin.ts
+++ b/vike/node/plugin/plugins/extractExportNamesPlugin.ts
@@ -3,10 +3,10 @@ export { isUsingClientRouter }
 export { extractExportNamesRE }
 
 import type { Plugin } from 'vite'
-import { assert, getFileExtension, viteIsSSR_options, createDebugger, getGlobalObject, assertUsage } from '../utils.js'
-import { getExportNames } from '../shared/parseEsModule.js'
-import { sourceMapRemove } from '../shared/rollupSourceMap.js'
-import { normalizeId } from '../shared/normalizeId.js'
+import { assert, getFileExtension, viteIsSSR_options, createDebugger, getGlobalObject, assertUsage } from '../utils'
+import { getExportNames } from '../shared/parseEsModule'
+import { sourceMapRemove } from '../shared/rollupSourceMap'
+import { normalizeId } from '../shared/normalizeId'
 const extractExportNamesRE = /(\?|&)extractExportNames(?:&|$)/
 const debug = createDebugger('vike:extractExportNames')
 const globalObject = getGlobalObject<{ usesClientRouter?: true }>('extractExportNamesPlugin.ts', {})
diff --git a/vike/node/plugin/plugins/fileEnv.ts b/vike/node/plugin/plugins/fileEnv.ts
index 3baaf12b27..100937f38f 100644
--- a/vike/node/plugin/plugins/fileEnv.ts
+++ b/vike/node/plugin/plugins/fileEnv.ts
@@ -6,14 +6,14 @@ export { fileEnv }
 // - SvelteKit: https://github.com/sveltejs/kit/blob/6ea7abbc2f66e46cb83ff95cd459a5f548cb7e1e/packages/kit/src/exports/vite/index.js#L383-L401
 
 import type { Plugin, ResolvedConfig, ViteDevServer } from 'vite'
-import { assert, assertUsage, assertWarning, capitalizeFirstLetter, joinEnglish } from '../utils.js'
-import { extractAssetsRE } from './extractAssetsPlugin.js'
-import { extractExportNamesRE } from './extractExportNamesPlugin.js'
+import { assert, assertUsage, assertWarning, capitalizeFirstLetter, joinEnglish } from '../utils'
+import { extractAssetsRE } from './extractAssetsPlugin'
+import { extractExportNamesRE } from './extractExportNamesPlugin'
 import pc from '@brillout/picocolors'
-import { getModuleFilePathAbsolute } from '../shared/getFilePath.js'
-import { sourceMapRemove } from '../shared/rollupSourceMap.js'
-import { getExportNames } from '../shared/parseEsModule.js'
-import { normalizeId } from '../shared/normalizeId.js'
+import { getModuleFilePathAbsolute } from '../shared/getFilePath'
+import { sourceMapRemove } from '../shared/rollupSourceMap'
+import { getExportNames } from '../shared/parseEsModule'
+import { normalizeId } from '../shared/normalizeId'
 
 function fileEnv(): Plugin {
   let config: ResolvedConfig
diff --git a/vike/node/plugin/plugins/importBuild/getVikeManifest.ts b/vike/node/plugin/plugins/importBuild/getVikeManifest.ts
index 002ed54a5f..943f73b334 100644
--- a/vike/node/plugin/plugins/importBuild/getVikeManifest.ts
+++ b/vike/node/plugin/plugins/importBuild/getVikeManifest.ts
@@ -1,10 +1,10 @@
 export { getVikeManifest }
 
-import { projectInfo } from '../../utils.js'
-import { type PluginManifest, assertPluginManifest } from '../../../shared/assertPluginManifest.js'
-import { isUsingClientRouter } from '../extractExportNamesPlugin.js'
-import type { ConfigVikeResolved } from '../../../../shared/ConfigVike.js'
-import { getRuntimeManifest } from '../../../runtime/globalContext.js'
+import { projectInfo } from '../../utils'
+import { type PluginManifest, assertPluginManifest } from '../../../shared/assertPluginManifest'
+import { isUsingClientRouter } from '../extractExportNamesPlugin'
+import type { ConfigVikeResolved } from '../../../../shared/ConfigVike'
+import { getRuntimeManifest } from '../../../runtime/globalContext'
 
 function getVikeManifest(configVike: ConfigVikeResolved): PluginManifest {
   const runtimeManifest = getRuntimeManifest(configVike)
diff --git a/vike/node/plugin/plugins/importBuild/index.ts b/vike/node/plugin/plugins/importBuild/index.ts
index f69e8c3f6f..64f6f5e5c3 100644
--- a/vike/node/plugin/plugins/importBuild/index.ts
+++ b/vike/node/plugin/plugins/importBuild/index.ts
@@ -3,14 +3,14 @@ export { set_ASSETS_MAP }
 
 import type { Plugin, ResolvedConfig, Rollup } from 'vite'
 import { serverProductionEntryPlugin } from '@brillout/vite-plugin-server-entry/plugin'
-import { assert, getOutDirs, toPosixPath } from '../../utils.js'
+import { assert, getOutDirs, toPosixPath } from '../../utils'
 import path from 'path'
 import { createRequire } from 'module'
-import { getConfigVike } from '../../../shared/getConfigVike.js'
-import type { ConfigVikeResolved } from '../../../../shared/ConfigVike.js'
-import { getVikeManifest } from './getVikeManifest.js'
+import { getConfigVike } from '../../../shared/getConfigVike'
+import type { ConfigVikeResolved } from '../../../../shared/ConfigVike'
+import { getVikeManifest } from './getVikeManifest'
 import fs from 'fs/promises'
-import { virtualFileIdImportUserCodeServer } from '../../../shared/virtual-files/virtualFileImportUserCode.js'
+import { virtualFileIdImportUserCodeServer } from '../../../shared/virtual-files/virtualFileImportUserCode'
 // @ts-ignore Shimmed by dist-cjs-fixup.js for CJS build.
 const importMetaUrl: string = import.meta.url
 const require_ = createRequire(importMetaUrl)
diff --git a/vike/node/plugin/plugins/importUserCode/getVirtualFileImportUserCode.ts b/vike/node/plugin/plugins/importUserCode/getVirtualFileImportUserCode.ts
index 4d6df65e01..2a39d25a04 100644
--- a/vike/node/plugin/plugins/importUserCode/getVirtualFileImportUserCode.ts
+++ b/vike/node/plugin/plugins/importUserCode/getVirtualFileImportUserCode.ts
@@ -16,14 +16,14 @@ import {
   getOutDirs,
   isVersionOrAbove,
   assertWarning
-} from '../../utils.js'
-import type { ConfigVikeResolved } from '../../../../shared/ConfigVike.js'
-import { isVirtualFileIdImportUserCode } from '../../../shared/virtual-files/virtualFileImportUserCode.js'
+} from '../../utils'
+import type { ConfigVikeResolved } from '../../../../shared/ConfigVike'
+import { isVirtualFileIdImportUserCode } from '../../../shared/virtual-files/virtualFileImportUserCode'
 import { version as viteVersion } from 'vite'
-import { type FileType, fileTypes } from '../../../../shared/getPageFiles/fileTypes.js'
+import { type FileType, fileTypes } from '../../../../shared/getPageFiles/fileTypes'
 import path from 'path'
-import { getVirtualFilePageConfigs } from './v1-design/getVirtualFilePageConfigs.js'
-import { isV1Design as isV1Design_ } from './v1-design/getVikeConfig.js'
+import { getVirtualFilePageConfigs } from './v1-design/getVirtualFilePageConfigs'
+import { isV1Design as isV1Design_ } from './v1-design/getVikeConfig'
 
 type GlobRoot = {
   includeDir: string // slash-terminated
diff --git a/vike/node/plugin/plugins/importUserCode/index.ts b/vike/node/plugin/plugins/importUserCode/index.ts
index d1c5972215..6dcb89c790 100644
--- a/vike/node/plugin/plugins/importUserCode/index.ts
+++ b/vike/node/plugin/plugins/importUserCode/index.ts
@@ -2,10 +2,10 @@ export { importUserCode }
 
 import type { Plugin, ResolvedConfig, HmrContext, ViteDevServer, ModuleNode } from 'vite'
 import { normalizePath } from 'vite'
-import type { ConfigVikeResolved } from '../../../../shared/ConfigVike.js'
-import { getConfigVike } from '../../../shared/getConfigVike.js'
-import { getVirtualFilePageConfigValuesAll } from './v1-design/getVirtualFilePageConfigValuesAll.js'
-import { getVirtualFileImportUserCode } from './getVirtualFileImportUserCode.js'
+import type { ConfigVikeResolved } from '../../../../shared/ConfigVike'
+import { getConfigVike } from '../../../shared/getConfigVike'
+import { getVirtualFilePageConfigValuesAll } from './v1-design/getVirtualFilePageConfigValuesAll'
+import { getVirtualFileImportUserCode } from './getVirtualFileImportUserCode'
 import {
   assert,
   assertPosixPath,
@@ -14,13 +14,13 @@ import {
   isDev3,
   isVirtualFileId,
   resolveVirtualFileId
-} from '../../utils.js'
-import { isVirtualFileIdPageConfigValuesAll } from '../../../shared/virtual-files/virtualFilePageConfigValuesAll.js'
-import { isVirtualFileIdImportUserCode } from '../../../shared/virtual-files/virtualFileImportUserCode.js'
-import { vikeConfigDependencies, reloadVikeConfig, isVikeConfigFile, isV1Design } from './v1-design/getVikeConfig.js'
+} from '../../utils'
+import { isVirtualFileIdPageConfigValuesAll } from '../../../shared/virtual-files/virtualFilePageConfigValuesAll'
+import { isVirtualFileIdImportUserCode } from '../../../shared/virtual-files/virtualFileImportUserCode'
+import { vikeConfigDependencies, reloadVikeConfig, isVikeConfigFile, isV1Design } from './v1-design/getVikeConfig'
 import pc from '@brillout/picocolors'
-import { logConfigInfo } from '../../shared/loggerNotProd.js'
-import { getModuleFilePathAbsolute } from '../../shared/getFilePath.js'
+import { logConfigInfo } from '../../shared/loggerNotProd'
+import { getModuleFilePathAbsolute } from '../../shared/getFilePath'
 
 function importUserCode(): Plugin {
   let config: ResolvedConfig
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/assertExtensions.ts b/vike/node/plugin/plugins/importUserCode/v1-design/assertExtensions.ts
index c1d2e64375..34c2bce686 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/assertExtensions.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/assertExtensions.ts
@@ -2,9 +2,9 @@ export { assertExtensionsConventions }
 export { assertExtensionsPeerDependencies }
 
 import pc from '@brillout/picocolors'
-import { isObjectOfStrings } from '../../../../../utils/isObjectOfStrings.js'
-import { PROJECT_VERSION, assert, assertUsage, assertWarning, findPackageJson } from '../../../utils.js'
-import { getConfigValueInterfaceFile, type InterfaceFile } from './getVikeConfig.js'
+import { isObjectOfStrings } from '../../../../../utils/isObjectOfStrings'
+import { PROJECT_VERSION, assert, assertUsage, assertWarning, findPackageJson } from '../../../utils'
+import { getConfigValueInterfaceFile, type InterfaceFile } from './getVikeConfig'
 import path from 'path'
 import semver from 'semver'
 
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/debug.ts b/vike/node/plugin/plugins/importUserCode/v1-design/debug.ts
index aeb76e8485..41333f0b37 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/debug.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/debug.ts
@@ -1,2 +1,2 @@
-import { createDebugger } from '../../../utils.js'
+import { createDebugger } from '../../../utils'
 export const debug = createDebugger('vike:virtual-files')
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getConfigFileExport.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getConfigFileExport.ts
index 8e5ff1f7a5..9d80edf42a 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getConfigFileExport.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getConfigFileExport.ts
@@ -1,8 +1,8 @@
 export { getConfigFileExport }
 
 import pc from '@brillout/picocolors'
-import { assertPlusFileExport } from '../../../../../shared/page-configs/assertPlusFileExport.js'
-import { assertUsage, isObject } from '../../../utils.js'
+import { assertPlusFileExport } from '../../../../../shared/page-configs/assertPlusFileExport'
+import { assertUsage, isObject } from '../../../utils'
 
 function getConfigFileExport(
   fileExports: Record<string, unknown>,
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig.ts
index f53b7b0996..f031391e7d 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig.ts
@@ -28,7 +28,7 @@ import {
   makeFirst,
   isNpmPackageImport,
   reverse
-} from '../../../utils.js'
+} from '../../../utils'
 import path from 'path'
 import type {
   PageConfigGlobalBuildTime,
@@ -38,15 +38,15 @@ import type {
   PageConfigBuildTime,
   DefinedAtFilePath,
   ConfigValuesComputed
-} from '../../../../../shared/page-configs/PageConfig.js'
-import type { Config } from '../../../../../shared/page-configs/Config.js'
+} from '../../../../../shared/page-configs/PageConfig'
+import type { Config } from '../../../../../shared/page-configs/Config'
 import {
   configDefinitionsBuiltIn,
   configDefinitionsBuiltInGlobal,
   type ConfigDefinitions,
   type ConfigDefinitionInternal,
   type ConfigNameGlobal
-} from './getVikeConfig/configDefinitionsBuiltIn.js'
+} from './getVikeConfig/configDefinitionsBuiltIn'
 import {
   type LocationId,
   getLocationId,
@@ -56,33 +56,33 @@ import {
   sortAfterInheritanceOrder,
   isGlobalLocation,
   applyFilesystemRoutingRootEffect
-} from './getVikeConfig/filesystemRouting.js'
-import { isTemporaryBuildFile } from './getVikeConfig/transpileAndExecuteFile.js'
-import { isConfigInvalid, isConfigInvalid_set } from '../../../../runtime/renderPage/isConfigInvalid.js'
-import { getViteDevServer } from '../../../../runtime/globalContext.js'
-import { logConfigError, logConfigErrorRecover } from '../../../shared/loggerNotProd.js'
+} from './getVikeConfig/filesystemRouting'
+import { isTemporaryBuildFile } from './getVikeConfig/transpileAndExecuteFile'
+import { isConfigInvalid, isConfigInvalid_set } from '../../../../runtime/renderPage/isConfigInvalid'
+import { getViteDevServer } from '../../../../runtime/globalContext'
+import { logConfigError, logConfigErrorRecover } from '../../../shared/loggerNotProd'
 import {
   removeSuperfluousViteLog_enable,
   removeSuperfluousViteLog_disable
-} from '../../../shared/loggerVite/removeSuperfluousViteLog.js'
+} from '../../../shared/loggerVite/removeSuperfluousViteLog'
 import pc from '@brillout/picocolors'
-import { getConfigDefinedAt } from '../../../../../shared/page-configs/getConfigDefinedAt.js'
+import { getConfigDefinedAt } from '../../../../../shared/page-configs/getConfigDefinedAt'
 import type { ResolvedConfig } from 'vite'
-import { crawlPlusFiles } from './getVikeConfig/crawlPlusFiles.js'
-import { getConfigFileExport } from './getConfigFileExport.js'
+import { crawlPlusFiles } from './getVikeConfig/crawlPlusFiles'
+import { getConfigFileExport } from './getConfigFileExport'
 import {
   type ConfigFile,
   ImportedFilesLoaded,
   loadConfigFile,
   loadImportedFile,
   loadValueFile
-} from './getVikeConfig/loadFileAtConfigTime.js'
-import { clearFilesEnvMap, resolvePointerImportOfConfig } from './getVikeConfig/resolvePointerImport.js'
-import { getFilePathResolved } from '../../../shared/getFilePath.js'
-import type { FilePathResolved } from '../../../../../shared/page-configs/FilePath.js'
-import { getConfigValueBuildTime } from '../../../../../shared/page-configs/getConfigValueBuildTime.js'
-import { getConfigVike } from '../../../../shared/getConfigVike.js'
-import { assertExtensionsPeerDependencies, assertExtensionsConventions } from './assertExtensions.js'
+} from './getVikeConfig/loadFileAtConfigTime'
+import { clearFilesEnvMap, resolvePointerImportOfConfig } from './getVikeConfig/resolvePointerImport'
+import { getFilePathResolved } from '../../../shared/getFilePath'
+import type { FilePathResolved } from '../../../../../shared/page-configs/FilePath'
+import { getConfigValueBuildTime } from '../../../../../shared/page-configs/getConfigValueBuildTime'
+import { getConfigVike } from '../../../../shared/getConfigVike'
+import { assertExtensionsPeerDependencies, assertExtensionsConventions } from './assertExtensions'
 
 assertIsNotProductionRuntime()
 
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/configDefinitionsBuiltIn.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/configDefinitionsBuiltIn.ts
index ebd885279d..8d30b69259 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/configDefinitionsBuiltIn.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/configDefinitionsBuiltIn.ts
@@ -12,10 +12,10 @@ import type {
   ConfigValueSources,
   DefinedAtFilePath,
   ConfigValueSource
-} from '../../../../../../shared/page-configs/PageConfig.js'
-import type { Config, ConfigNameBuiltIn } from '../../../../../../shared/page-configs/Config.js'
-import { assert, assertUsage } from '../../../../utils.js'
-import { getConfigDefinedAt, type ConfigDefinedAt } from '../../../../../../shared/page-configs/getConfigDefinedAt.js'
+} from '../../../../../../shared/page-configs/PageConfig'
+import type { Config, ConfigNameBuiltIn } from '../../../../../../shared/page-configs/Config'
+import { assert, assertUsage } from '../../../../utils'
+import { getConfigDefinedAt, type ConfigDefinedAt } from '../../../../../../shared/page-configs/getConfigDefinedAt'
 
 // For users
 /** The meta definition of a config.
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/crawlPlusFiles.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/crawlPlusFiles.ts
index 5cb4163a48..9584ca22b9 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/crawlPlusFiles.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/crawlPlusFiles.ts
@@ -10,7 +10,7 @@ import {
   assertIsNotProductionRuntime,
   isVersionOrAbove,
   isScriptFile
-} from '../../../../utils.js'
+} from '../../../../utils'
 import path from 'path'
 import fs from 'fs/promises'
 import type { Stats } from 'fs'
@@ -18,7 +18,7 @@ import glob from 'fast-glob'
 import { exec } from 'child_process'
 import { promisify } from 'util'
 import pc from '@brillout/picocolors'
-import { isTemporaryBuildFile } from './transpileAndExecuteFile.js'
+import { isTemporaryBuildFile } from './transpileAndExecuteFile'
 const execA = promisify(exec)
 const TOO_MANY_UNTRACKED_FILES = 5
 
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting.spec.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting.spec.ts
index 29d3947d0c..4ddc3e8e5c 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting.spec.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting.spec.ts
@@ -3,7 +3,7 @@ import {
   isInherited as isInherited_,
   getLogicalPath as getLogicalPath_,
   type LocationId
-} from './filesystemRouting.js'
+} from './filesystemRouting'
 import { expect, describe, it } from 'vitest'
 
 describe('getLocationId()', () => {
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting.ts
index aaa0bd87b7..39076250d6 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting.ts
@@ -11,7 +11,7 @@ export type { LocationId }
 export { getLogicalPath }
 
 import pc from '@brillout/picocolors'
-import { assert, assertIsNotProductionRuntime, assertPosixPath, assertWarning, higherFirst } from '../../../../utils.js'
+import { assert, assertIsNotProductionRuntime, assertPosixPath, assertWarning, higherFirst } from '../../../../utils'
 assertIsNotProductionRuntime()
 
 /**
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/loadFileAtConfigTime.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/loadFileAtConfigTime.ts
index c40f0277fb..539bf40ad5 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/loadFileAtConfigTime.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/loadFileAtConfigTime.ts
@@ -6,15 +6,15 @@ export { loadConfigFile }
 export type { ImportedFilesLoaded }
 export type { ConfigFile }
 
-import { assert, assertUsage, hasProp, assertIsNotProductionRuntime } from '../../../../utils.js'
-import type { FilePathResolved } from '../../../../../../shared/page-configs/FilePath.js'
-import { transpileAndExecuteFile } from './transpileAndExecuteFile.js'
-import type { InterfaceValueFile } from '../getVikeConfig.js'
-import { assertPlusFileExport } from '../../../../../../shared/page-configs/assertPlusFileExport.js'
+import { assert, assertUsage, hasProp, assertIsNotProductionRuntime } from '../../../../utils'
+import type { FilePathResolved } from '../../../../../../shared/page-configs/FilePath'
+import { transpileAndExecuteFile } from './transpileAndExecuteFile'
+import type { InterfaceValueFile } from '../getVikeConfig'
+import { assertPlusFileExport } from '../../../../../../shared/page-configs/assertPlusFileExport'
 import pc from '@brillout/picocolors'
-import { type PointerImportData, parsePointerImportData } from './transformPointerImports.js'
-import { getConfigFileExport } from '../getConfigFileExport.js'
-import { resolvePointerImport } from './resolvePointerImport.js'
+import { type PointerImportData, parsePointerImportData } from './transformPointerImports'
+import { getConfigFileExport } from '../getConfigFileExport'
+import { resolvePointerImport } from './resolvePointerImport'
 
 assertIsNotProductionRuntime()
 
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/resolvePointerImport.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/resolvePointerImport.ts
index 17f8554fd2..0371448aea 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/resolvePointerImport.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/resolvePointerImport.ts
@@ -3,7 +3,7 @@ export { resolvePointerImport }
 export { clearFilesEnvMap }
 
 import pc from '@brillout/picocolors'
-import type { ConfigEnvInternal, DefinedAtFilePath } from '../../../../../../shared/page-configs/PageConfig.js'
+import type { ConfigEnvInternal, DefinedAtFilePath } from '../../../../../../shared/page-configs/PageConfig'
 import {
   assert,
   assertIsNpmPackageImport,
@@ -12,15 +12,15 @@ import {
   deepEqual,
   isFilePathAbsolute,
   requireResolve
-} from '../../../../utils.js'
-import { type PointerImportData, parsePointerImportData } from './transformPointerImports.js'
+} from '../../../../utils'
+import { type PointerImportData, parsePointerImportData } from './transformPointerImports'
 import path from 'path'
 import {
   getFilePathAbsoluteUserRootDir,
   getFilePathResolved,
   getFilePathUnresolved
-} from '../../../../shared/getFilePath.js'
-import type { FilePath, FilePathResolved } from '../../../../../../shared/page-configs/FilePath.js'
+} from '../../../../shared/getFilePath'
+import type { FilePath, FilePathResolved } from '../../../../../../shared/page-configs/FilePath'
 
 const filesEnvMap: Map<string, { configEnv: ConfigEnvInternal; configName: string }[]> = new Map()
 
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports.spec.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports.spec.ts
index 890d55ee51..bd3d0de45d 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports.spec.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports.spec.ts
@@ -1,5 +1,5 @@
 import { expect, describe, it } from 'vitest'
-import { transformPointerImports } from './transformPointerImports.js'
+import { transformPointerImports } from './transformPointerImports'
 
 function t(code: string) {
   return transformPointerImports(code, '/fake-file.js', 'all', true)
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports.ts
index 30a4d00677..0eff741ea3 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports.ts
@@ -22,7 +22,7 @@ export type { PointerImportData }
 
 import { parse } from 'acorn'
 import type { Program, Identifier, ImportDeclaration } from 'estree'
-import { assert, assertUsage, assertWarning, styleFileRE } from '../../../../utils.js'
+import { assert, assertUsage, assertWarning, styleFileRE } from '../../../../utils'
 import pc from '@brillout/picocolors'
 
 function transformPointerImports(
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transpileAndExecuteFile.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transpileAndExecuteFile.ts
index c644a133f2..1b876f0afd 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transpileAndExecuteFile.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transpileAndExecuteFile.ts
@@ -30,12 +30,12 @@ import {
   createDebugger,
   assertFilePathAbsoluteFilesystem,
   assertIsNpmPackageImport
-} from '../../../../utils.js'
-import { transformPointerImports } from './transformPointerImports.js'
-import { vikeConfigDependencies } from '../getVikeConfig.js'
-import 'source-map-support/register.js'
-import type { FilePathResolved } from '../../../../../../shared/page-configs/FilePath.js'
-import { getFilePathAbsoluteUserRootDir } from '../../../../shared/getFilePath.js'
+} from '../../../../utils'
+import { transformPointerImports } from './transformPointerImports'
+import { vikeConfigDependencies } from '../getVikeConfig'
+import 'source-map-support/register'
+import type { FilePathResolved } from '../../../../../../shared/page-configs/FilePath'
+import { getFilePathAbsoluteUserRootDir } from '../../../../shared/getFilePath'
 import { createRequire } from 'module'
 // @ts-ignore Shimmed by dist-cjs-fixup.js for CJS build.
 const importMetaUrl: string = import.meta.url
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVirtualFilePageConfigValuesAll.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVirtualFilePageConfigValuesAll.ts
index caa3a35d04..b4d6d3be21 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVirtualFilePageConfigValuesAll.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVirtualFilePageConfigValuesAll.ts
@@ -1,20 +1,20 @@
 export { getVirtualFilePageConfigValuesAll }
 
-import { assert } from '../../../utils.js'
-import type { PageConfigBuildTime } from '../../../../../shared/page-configs/PageConfig.js'
+import { assert } from '../../../utils'
+import type { PageConfigBuildTime } from '../../../../../shared/page-configs/PageConfig'
 import {
   getVirtualFileIdPageConfigValuesAll,
   isVirtualFileIdPageConfigValuesAll
-} from '../../../../shared/virtual-files/virtualFilePageConfigValuesAll.js'
-import { getVikeConfig } from './getVikeConfig.js'
-import { extractAssetsAddQuery } from '../../../../shared/extractAssetsQuery.js'
-import { debug } from './debug.js'
-import { isRuntimeEnvMatch } from './isRuntimeEnvMatch.js'
-import { serializeConfigValues } from '../../../../../shared/page-configs/serialize/serializeConfigValues.js'
+} from '../../../../shared/virtual-files/virtualFilePageConfigValuesAll'
+import { getVikeConfig } from './getVikeConfig'
+import { extractAssetsAddQuery } from '../../../../shared/extractAssetsQuery'
+import { debug } from './debug'
+import { isRuntimeEnvMatch } from './isRuntimeEnvMatch'
+import { serializeConfigValues } from '../../../../../shared/page-configs/serialize/serializeConfigValues'
 import type { ResolvedConfig } from 'vite'
-import { getConfigVike } from '../../../../shared/getConfigVike.js'
-import { fixServerAssets_isEnabled } from '../../buildConfig/fixServerAssets.js'
-import { getConfigValueBuildTime } from '../../../../../shared/page-configs/getConfigValueBuildTime.js'
+import { getConfigVike } from '../../../../shared/getConfigVike'
+import { fixServerAssets_isEnabled } from '../../buildConfig/fixServerAssets'
+import { getConfigValueBuildTime } from '../../../../../shared/page-configs/getConfigValueBuildTime'
 
 async function getVirtualFilePageConfigValuesAll(id: string, isDev: boolean, config: ResolvedConfig): Promise<string> {
   const result = isVirtualFileIdPageConfigValuesAll(id)
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/getVirtualFilePageConfigs.ts b/vike/node/plugin/plugins/importUserCode/v1-design/getVirtualFilePageConfigs.ts
index 426c4d5f1b..0b01d088d1 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/getVirtualFilePageConfigs.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/getVirtualFilePageConfigs.ts
@@ -1,11 +1,11 @@
 export { getVirtualFilePageConfigs }
 
-import type { PageConfigBuildTime, PageConfigGlobalBuildTime } from '../../../../../shared/page-configs/PageConfig.js'
-import { getVirtualFileIdPageConfigValuesAll } from '../../../../shared/virtual-files/virtualFilePageConfigValuesAll.js'
-import { debug } from './debug.js'
-import { getVikeConfig } from './getVikeConfig.js'
-import { isRuntimeEnvMatch } from './isRuntimeEnvMatch.js'
-import { serializeConfigValues } from '../../../../../shared/page-configs/serialize/serializeConfigValues.js'
+import type { PageConfigBuildTime, PageConfigGlobalBuildTime } from '../../../../../shared/page-configs/PageConfig'
+import { getVirtualFileIdPageConfigValuesAll } from '../../../../shared/virtual-files/virtualFilePageConfigValuesAll'
+import { debug } from './debug'
+import { getVikeConfig } from './getVikeConfig'
+import { isRuntimeEnvMatch } from './isRuntimeEnvMatch'
+import { serializeConfigValues } from '../../../../../shared/page-configs/serialize/serializeConfigValues'
 import type { ResolvedConfig } from 'vite'
 
 async function getVirtualFilePageConfigs(
diff --git a/vike/node/plugin/plugins/importUserCode/v1-design/isRuntimeEnvMatch.ts b/vike/node/plugin/plugins/importUserCode/v1-design/isRuntimeEnvMatch.ts
index fc3c13bb2c..f2c682cb38 100644
--- a/vike/node/plugin/plugins/importUserCode/v1-design/isRuntimeEnvMatch.ts
+++ b/vike/node/plugin/plugins/importUserCode/v1-design/isRuntimeEnvMatch.ts
@@ -1,6 +1,6 @@
 export { isRuntimeEnvMatch }
 
-import type { ConfigEnvInternal } from '../../../../../shared/page-configs/PageConfig.js'
+import type { ConfigEnvInternal } from '../../../../../shared/page-configs/PageConfig'
 
 function isRuntimeEnvMatch(
   configEnv: ConfigEnvInternal,
diff --git a/vike/node/plugin/plugins/packageJsonFile.ts b/vike/node/plugin/plugins/packageJsonFile.ts
index c660aa7de1..4f4423aa35 100644
--- a/vike/node/plugin/plugins/packageJsonFile.ts
+++ b/vike/node/plugin/plugins/packageJsonFile.ts
@@ -10,8 +10,8 @@
 export { packageJsonFile }
 
 import type { Plugin, ResolvedConfig } from 'vite'
-import { rollupIsEsm } from '../shared/rollupIsEsm.js'
-import { viteIsSSR } from '../utils.js'
+import { rollupIsEsm } from '../shared/rollupIsEsm'
+import { viteIsSSR } from '../utils'
 
 function packageJsonFile(): Plugin {
   let config: ResolvedConfig
diff --git a/vike/node/plugin/plugins/previewConfig.ts b/vike/node/plugin/plugins/previewConfig.ts
index 13cd0c7373..c8db2bcb85 100644
--- a/vike/node/plugin/plugins/previewConfig.ts
+++ b/vike/node/plugin/plugins/previewConfig.ts
@@ -1,13 +1,13 @@
 export { previewConfig }
 
 import type { Plugin, ResolvedConfig } from 'vite'
-import { assertUsage, getOutDirs, resolveOutDir, markEnvAsVitePreview } from '../utils.js'
-import { getConfigVike } from '../../shared/getConfigVike.js'
+import { assertUsage, getOutDirs, resolveOutDir, markEnvAsVitePreview } from '../utils'
+import { getConfigVike } from '../../shared/getConfigVike'
 import fs from 'fs'
 import path from 'path'
 import type { ViteDevServer } from 'vite'
-import type { ConfigVikeResolved } from '../../../shared/ConfigVike.js'
-import { addSsrMiddleware } from '../shared/addSsrMiddleware.js'
+import type { ConfigVikeResolved } from '../../../shared/ConfigVike'
+import { addSsrMiddleware } from '../shared/addSsrMiddleware'
 import pc from '@brillout/picocolors'
 type ConnectServer = ViteDevServer['middlewares']
 
diff --git a/vike/node/plugin/plugins/setGlobalContext.ts b/vike/node/plugin/plugins/setGlobalContext.ts
index 6b98925aa8..f845a7c44c 100644
--- a/vike/node/plugin/plugins/setGlobalContext.ts
+++ b/vike/node/plugin/plugins/setGlobalContext.ts
@@ -5,8 +5,8 @@ import {
   setGlobalContext_isDev,
   setGlobalContext_viteDevServer,
   setGlobalContext_viteConfig
-} from '../../runtime/globalContext.js'
-import { assertFilePathAbsoluteFilesystem, getOutDirs, isDev3 } from '../utils.js'
+} from '../../runtime/globalContext'
+import { assertFilePathAbsoluteFilesystem, getOutDirs, isDev3 } from '../utils'
 
 function setGlobalContext(): Plugin {
   return {
diff --git a/vike/node/plugin/resolveClientEntriesDev.ts b/vike/node/plugin/resolveClientEntriesDev.ts
index 815b4424ae..b98b03a831 100644
--- a/vike/node/plugin/resolveClientEntriesDev.ts
+++ b/vike/node/plugin/resolveClientEntriesDev.ts
@@ -8,7 +8,7 @@ import {
   pathJoin,
   assertIsNpmPackageImport,
   assertIsNotProductionRuntime
-} from './utils.js'
+} from './utils'
 import type { ViteDevServer } from 'vite'
 import { createRequire } from 'module'
 import { dirname } from 'path'
diff --git a/vike/node/plugin/shared/addSsrMiddleware.ts b/vike/node/plugin/shared/addSsrMiddleware.ts
index 383f7e9f0e..d62c297abe 100644
--- a/vike/node/plugin/shared/addSsrMiddleware.ts
+++ b/vike/node/plugin/shared/addSsrMiddleware.ts
@@ -1,8 +1,8 @@
 export { addSsrMiddleware }
 
-import { renderPage } from '../../runtime/renderPage.js'
+import { renderPage } from '../../runtime/renderPage'
 import type { ResolvedConfig, ViteDevServer } from 'vite'
-import { assertWarning } from '../utils.js'
+import { assertWarning } from '../utils'
 import pc from '@brillout/picocolors'
 type ConnectServer = ViteDevServer['middlewares']
 
diff --git a/vike/node/plugin/shared/findPageFiles.ts b/vike/node/plugin/shared/findPageFiles.ts
index 6f41ae5f05..ebbf5dca4d 100644
--- a/vike/node/plugin/shared/findPageFiles.ts
+++ b/vike/node/plugin/shared/findPageFiles.ts
@@ -2,8 +2,8 @@ export { findPageFiles }
 
 import glob from 'fast-glob'
 import type { ResolvedConfig } from 'vite'
-import { assertWarning, toPosixPath, scriptFileExtensions, getOutDirs } from '../utils.js'
-import type { FileType } from '../../../shared/getPageFiles/fileTypes.js'
+import { assertWarning, toPosixPath, scriptFileExtensions, getOutDirs } from '../utils'
+import type { FileType } from '../../../shared/getPageFiles/fileTypes'
 import pc from '@brillout/picocolors'
 
 async function findPageFiles(config: ResolvedConfig, fileTypes: FileType[], isDev: boolean): Promise<string[]> {
diff --git a/vike/node/plugin/shared/getAssetsDir.ts b/vike/node/plugin/shared/getAssetsDir.ts
index 6cd4006482..9ea5d6264a 100644
--- a/vike/node/plugin/shared/getAssetsDir.ts
+++ b/vike/node/plugin/shared/getAssetsDir.ts
@@ -1,7 +1,7 @@
 export { getAssetsDir }
 
 import type { ResolvedConfig } from 'vite'
-import { assertUsage } from '../utils.js'
+import { assertUsage } from '../utils'
 
 function getAssetsDir(config: ResolvedConfig) {
   let { assetsDir } = config.build
diff --git a/vike/node/plugin/shared/getFilePath.ts b/vike/node/plugin/shared/getFilePath.ts
index 6aa51c94b2..07ada4acb0 100644
--- a/vike/node/plugin/shared/getFilePath.ts
+++ b/vike/node/plugin/shared/getFilePath.ts
@@ -14,8 +14,8 @@ import {
   assertFilePathAbsoluteFilesystem,
   assertPosixPath,
   toPosixPath
-} from '../utils.js'
-import type { FilePathResolved, FilePathUnresolved } from '../../../shared/page-configs/FilePath.js'
+} from '../utils'
+import type { FilePathResolved, FilePathUnresolved } from '../../../shared/page-configs/FilePath'
 import type { ResolvedConfig } from 'vite'
 
 function getFilePathResolved(
diff --git a/vike/node/plugin/shared/getHttpRequestAsyncStore.ts b/vike/node/plugin/shared/getHttpRequestAsyncStore.ts
index fbc151cd00..ffa253ea46 100644
--- a/vike/node/plugin/shared/getHttpRequestAsyncStore.ts
+++ b/vike/node/plugin/shared/getHttpRequestAsyncStore.ts
@@ -14,12 +14,12 @@
 export { getHttpRequestAsyncStore }
 export { installHttpRequestAsyncStore }
 
-import { renderPage_addWrapper } from '../../runtime/renderPage.js'
-import { assert, assertIsNotProductionRuntime, isObject, unique } from '../utils.js'
+import { renderPage_addWrapper } from '../../runtime/renderPage'
+import { assert, assertIsNotProductionRuntime, isObject, unique } from '../utils'
 import type { AsyncLocalStorage as AsyncLocalStorageType } from 'node:async_hooks'
-import { getConfigBuildErrorFormatted } from '../plugins/importUserCode/v1-design/getVikeConfig/transpileAndExecuteFile.js'
-import { logErrorDebugNote } from './loggerNotProd.js'
-import { isEquivalentErrorWithCodeSnippet } from './loggerNotProd/errorWithCodeSnippet.js'
+import { getConfigBuildErrorFormatted } from '../plugins/importUserCode/v1-design/getVikeConfig/transpileAndExecuteFile'
+import { logErrorDebugNote } from './loggerNotProd'
+import { isEquivalentErrorWithCodeSnippet } from './loggerNotProd/errorWithCodeSnippet'
 import { isDeepStrictEqual } from 'node:util'
 
 assertIsNotProductionRuntime()
diff --git a/vike/node/plugin/shared/isViteCliCall.ts b/vike/node/plugin/shared/isViteCliCall.ts
index db8d93e0f6..1ef8f78bdd 100644
--- a/vike/node/plugin/shared/isViteCliCall.ts
+++ b/vike/node/plugin/shared/isViteCliCall.ts
@@ -1,7 +1,7 @@
 export { isViteCliCall }
 export { getViteConfigFromCli }
 
-import { assert, isObject, toPosixPath } from '../utils.js'
+import { assert, isObject, toPosixPath } from '../utils'
 import { cac } from 'cac'
 
 function isViteCliCall(): boolean {
diff --git a/vike/node/plugin/shared/loggerNotProd.ts b/vike/node/plugin/shared/loggerNotProd.ts
index e313054475..3120b6fd1d 100644
--- a/vike/node/plugin/shared/loggerNotProd.ts
+++ b/vike/node/plugin/shared/loggerNotProd.ts
@@ -18,9 +18,9 @@ export type { LogErrorArgs }
 export type { LogType }
 export type { LogCategory }
 
-import { isAbortError } from '../../../shared/route/abort.js'
-import { getViteConfig } from '../../runtime/globalContext.js'
-import { overwriteRuntimeProductionLogger } from '../../runtime/renderPage/loggerRuntime.js'
+import { isAbortError } from '../../../shared/route/abort'
+import { getViteConfig } from '../../runtime/globalContext'
+import { overwriteRuntimeProductionLogger } from '../../runtime/renderPage/loggerRuntime'
 import {
   assert,
   assertIsNotProductionRuntime,
@@ -29,19 +29,19 @@ import {
   overwriteAssertProductionLogger,
   stripAnsi,
   warnIfErrorIsNotObject
-} from '../utils.js'
-import { getHttpRequestAsyncStore } from './getHttpRequestAsyncStore.js'
-import { isErrorDebug } from '../../shared/isErrorDebug.js'
-import { isErrorWithCodeSnippet, getPrettyErrorWithCodeSnippet } from './loggerNotProd/errorWithCodeSnippet.js'
+} from '../utils'
+import { getHttpRequestAsyncStore } from './getHttpRequestAsyncStore'
+import { isErrorDebug } from '../../shared/isErrorDebug'
+import { isErrorWithCodeSnippet, getPrettyErrorWithCodeSnippet } from './loggerNotProd/errorWithCodeSnippet'
 import {
   getConfigExecutionErrorIntroMsg,
   getConfigBuildErrorFormatted
-} from '../plugins/importUserCode/v1-design/getVikeConfig/transpileAndExecuteFile.js'
-import { logWithVikeTag, logWithViteTag, logDirectly, applyViteSourceMapToStackTrace } from './loggerNotProd/log.js'
+} from '../plugins/importUserCode/v1-design/getVikeConfig/transpileAndExecuteFile'
+import { logWithVikeTag, logWithViteTag, logDirectly, applyViteSourceMapToStackTrace } from './loggerNotProd/log'
 import pc from '@brillout/picocolors'
-import { setAlreadyLogged } from '../../runtime/renderPage/isNewError.js'
-import { onRuntimeError } from '../../runtime/renderPage/loggerProd.js'
-import { isUserHookError } from '../../../shared/hooks/executeHook.js'
+import { setAlreadyLogged } from '../../runtime/renderPage/isNewError'
+import { onRuntimeError } from '../../runtime/renderPage/loggerProd'
+import { isUserHookError } from '../../../shared/hooks/executeHook'
 
 assertIsNotProductionRuntime()
 overwriteRuntimeProductionLogger(logRuntimeError, logRuntimeInfo)
diff --git a/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet.ts b/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet.ts
index 0f2e761929..f1e4a156fe 100644
--- a/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet.ts
+++ b/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet.ts
@@ -12,8 +12,8 @@ export { getPrettyErrMessage }
 // Copied & adapted from https://github.com/vitejs/vite/blob/9c114c5c72a6af87e3330d5573362554b4511265/packages/vite/src/node/server/middlewares/error.ts
 
 import pc from '@brillout/picocolors'
-import { assert, escapeRegex, isObject, removeEmptyLines, stripAnsi } from '../../utils.js'
-import { cleanFilePathUnkown, getFilePathToShowToUserFromUnkown } from '../getFilePath.js'
+import { assert, escapeRegex, isObject, removeEmptyLines, stripAnsi } from '../../utils'
+import { cleanFilePathUnkown, getFilePathToShowToUserFromUnkown } from '../getFilePath'
 
 // Subset of RollupError
 type ErrorWithCodeSnippet = { id: string; frame?: string; message?: string; plugin?: string }
diff --git a/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet/getPrettyErrMessage.spec.ts b/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet/getPrettyErrMessage.spec.ts
index 11fba12a14..895e096bae 100644
--- a/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet/getPrettyErrMessage.spec.ts
+++ b/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet/getPrettyErrMessage.spec.ts
@@ -1,4 +1,4 @@
-import { getPrettyErrMessage } from '../errorWithCodeSnippet.js'
+import { getPrettyErrMessage } from '../errorWithCodeSnippet'
 
 import { expect, describe, it } from 'vitest'
 
diff --git a/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet/getPrettyErrorWithCodeSnippet.spec.ts b/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet/getPrettyErrorWithCodeSnippet.spec.ts
index 2f9e55bb64..255a65fa3e 100644
--- a/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet/getPrettyErrorWithCodeSnippet.spec.ts
+++ b/vike/node/plugin/shared/loggerNotProd/errorWithCodeSnippet/getPrettyErrorWithCodeSnippet.spec.ts
@@ -1,7 +1,7 @@
-import { getPrettyErrorWithCodeSnippet, isErrorWithCodeSnippet } from '../errorWithCodeSnippet.js'
+import { getPrettyErrorWithCodeSnippet, isErrorWithCodeSnippet } from '../errorWithCodeSnippet'
 
 import { expect, describe, it } from 'vitest'
-import { stripAnsi } from '../../../utils.js'
+import { stripAnsi } from '../../../utils'
 
 import { errBabelSolid } from './fixture-errors/errBabelSolid.js'
 import { errBabelReact } from './fixture-errors/errBabelReact.js'
diff --git a/vike/node/plugin/shared/loggerNotProd/log.ts b/vike/node/plugin/shared/loggerNotProd/log.ts
index 502ff7057c..ae681c04e9 100644
--- a/vike/node/plugin/shared/loggerNotProd/log.ts
+++ b/vike/node/plugin/shared/loggerNotProd/log.ts
@@ -3,11 +3,11 @@ export { logWithVikeTag }
 export { logDirectly }
 export { applyViteSourceMapToStackTrace }
 
-import { assert, projectInfo, stripAnsi, hasProp, assertIsNotProductionRuntime } from '../../utils.js'
+import { assert, projectInfo, stripAnsi, hasProp, assertIsNotProductionRuntime } from '../../utils'
 import pc from '@brillout/picocolors'
-import { isErrorDebug } from '../../../shared/isErrorDebug.js'
-import { getViteDevServer } from '../../../runtime/globalContext.js'
-import type { LogCategory, LogType } from '../loggerNotProd.js'
+import { isErrorDebug } from '../../../shared/isErrorDebug'
+import { getViteDevServer } from '../../../runtime/globalContext'
+import type { LogCategory, LogType } from '../loggerNotProd'
 
 assertIsNotProductionRuntime()
 
diff --git a/vike/node/plugin/shared/loggerVite.ts b/vike/node/plugin/shared/loggerVite.ts
index 909672506f..6909ed2059 100644
--- a/vike/node/plugin/shared/loggerVite.ts
+++ b/vike/node/plugin/shared/loggerVite.ts
@@ -1,11 +1,11 @@
 export { improveViteLogs }
 
-import { assert, removeEmptyLines, trimWithAnsi, trimWithAnsiTrailOnly } from '../utils.js'
-import { logViteError, logViteAny } from './loggerNotProd.js'
-import { getHttpRequestAsyncStore } from './getHttpRequestAsyncStore.js'
-import { removeSuperfluousViteLog } from './loggerVite/removeSuperfluousViteLog.js'
+import { assert, removeEmptyLines, trimWithAnsi, trimWithAnsiTrailOnly } from '../utils'
+import { logViteError, logViteAny } from './loggerNotProd'
+import { getHttpRequestAsyncStore } from './getHttpRequestAsyncStore'
+import { removeSuperfluousViteLog } from './loggerVite/removeSuperfluousViteLog'
 import type { LogType, ResolvedConfig, LogErrorOptions } from 'vite'
-import { isErrorDebug } from '../../shared/isErrorDebug.js'
+import { isErrorDebug } from '../../shared/isErrorDebug'
 
 function improveViteLogs(config: ResolvedConfig) {
   intercept('info', config)
diff --git a/vike/node/plugin/shared/loggerVite/removeSuperfluousViteLog.ts b/vike/node/plugin/shared/loggerVite/removeSuperfluousViteLog.ts
index d31754f0b7..2f24279f82 100644
--- a/vike/node/plugin/shared/loggerVite/removeSuperfluousViteLog.ts
+++ b/vike/node/plugin/shared/loggerVite/removeSuperfluousViteLog.ts
@@ -2,7 +2,7 @@ export { removeSuperfluousViteLog }
 export { removeSuperfluousViteLog_enable }
 export { removeSuperfluousViteLog_disable }
 
-import { assert } from '../../utils.js'
+import { assert } from '../../utils'
 
 const superfluousLog = 'Forced re-optimization of dependencies'
 let enabled = false
diff --git a/vike/node/plugin/shared/normalizeId.ts b/vike/node/plugin/shared/normalizeId.ts
index 3eae3fdafd..915b801ee0 100644
--- a/vike/node/plugin/shared/normalizeId.ts
+++ b/vike/node/plugin/shared/normalizeId.ts
@@ -1,6 +1,6 @@
 export { normalizeId }
 
-import { toPosixPath } from '../utils.js'
+import { toPosixPath } from '../utils'
 
 // In principle Vite/Rollup should always normalize the `id` in `transform(code, id)` but it seems to not always do it.
 // https://github.com/vikejs/vike/issues/1935
diff --git a/vike/node/plugin/shared/parseEsModule.ts b/vike/node/plugin/shared/parseEsModule.ts
index 71d1a32268..7751d0c912 100644
--- a/vike/node/plugin/shared/parseEsModule.ts
+++ b/vike/node/plugin/shared/parseEsModule.ts
@@ -3,7 +3,7 @@ export { getImportStatements }
 export type { ImportStatement }
 
 import { init, parse } from 'es-module-lexer'
-import { assert } from '../utils.js'
+import { assert } from '../utils'
 
 type ParseResult = ReturnType<typeof parse>
 type ImportStatement = ParseResult[0][0]
diff --git a/vike/node/plugin/shared/rollupIsEsm.ts b/vike/node/plugin/shared/rollupIsEsm.ts
index 9734237984..dc5af571f0 100644
--- a/vike/node/plugin/shared/rollupIsEsm.ts
+++ b/vike/node/plugin/shared/rollupIsEsm.ts
@@ -1,4 +1,4 @@
-import { assert } from '../utils.js'
+import { assert } from '../utils'
 export function rollupIsEsm(rollupOptions: { format: string }) {
   const { format } = rollupOptions
   assert(typeof format === 'string')
diff --git a/vike/node/plugin/utils.ts b/vike/node/plugin/utils.ts
index 0732203b40..d92f225ca4 100644
--- a/vike/node/plugin/utils.ts
+++ b/vike/node/plugin/utils.ts
@@ -1,32 +1,32 @@
 // Utils needed by Vike's Vite plugin.
 
 // We assume all runtime entries will load this utils.ts file
-import { onLoad } from './onLoad.js'
+import { onLoad } from './onLoad'
 onLoad()
 
 // We tolerate the fact that we load all of the runtime utils even though some of it isn't needed
-export * from '../runtime/utils.js'
+export * from '../runtime/utils'
 
 // Utils only needed by `plugin/*`
-export * from '../../utils/viteIsSSR.js'
-export * from '../../utils/requireResolve.js'
-export * from '../../utils/includes.js'
-export * from '../../utils/isDev.js'
-export * from '../../utils/getMostSimilar.js'
-export * from '../../utils/getRandomId.js'
-export * from '../../utils/joinEnglish.js'
-export * from '../../utils/escapeRegex.js'
-export * from '../../utils/stripAnsi.js'
-export * from '../../utils/trimWithAnsi.js'
-export * from '../../utils/removeEmptyLines.js'
-export * from '../../utils/findPackageJson.js'
-export * from '../../utils/getPropAccessNotation.js'
-export * from '../../utils/deepEqual.js'
-export * from '../../utils/assertKeys.js'
-export * from '../../utils/injectRollupInputs.js'
-export * from '../../utils/humanizeTime.js'
-export * from '../../utils/pLimit.js'
-export * from '../../utils/assertVersion.js'
-export * from '../../utils/isFilePathAbsoluteFilesystem.js'
-export * from '../../utils/isArray.js'
-export * from '../../utils/PROJECT_VERSION.js'
+export * from '../../utils/viteIsSSR'
+export * from '../../utils/requireResolve'
+export * from '../../utils/includes'
+export * from '../../utils/isDev'
+export * from '../../utils/getMostSimilar'
+export * from '../../utils/getRandomId'
+export * from '../../utils/joinEnglish'
+export * from '../../utils/escapeRegex'
+export * from '../../utils/stripAnsi'
+export * from '../../utils/trimWithAnsi'
+export * from '../../utils/removeEmptyLines'
+export * from '../../utils/findPackageJson'
+export * from '../../utils/getPropAccessNotation'
+export * from '../../utils/deepEqual'
+export * from '../../utils/assertKeys'
+export * from '../../utils/injectRollupInputs'
+export * from '../../utils/humanizeTime'
+export * from '../../utils/pLimit'
+export * from '../../utils/assertVersion'
+export * from '../../utils/isFilePathAbsoluteFilesystem'
+export * from '../../utils/isArray'
+export * from '../../utils/PROJECT_VERSION'
diff --git a/vike/node/prerender/index.ts b/vike/node/prerender/index.ts
index c6d487dd5f..e0cdbe4edd 100644
--- a/vike/node/prerender/index.ts
+++ b/vike/node/prerender/index.ts
@@ -1 +1 @@
-export { runPrerenderFromAPI as prerender } from './runPrerender.js'
+export { runPrerenderFromAPI as prerender } from './runPrerender'
diff --git a/vike/node/prerender/runPrerender.ts b/vike/node/prerender/runPrerender.ts
index 2a1d86c72f..577702965a 100644
--- a/vike/node/prerender/runPrerender.ts
+++ b/vike/node/prerender/runPrerender.ts
@@ -4,9 +4,9 @@ export { runPrerenderFromAutoFullBuild }
 export { runPrerender_forceExit }
 export type { PrerenderOptions }
 
-import '../runtime/page-files/setup.js'
+import '../runtime/page-files/setup'
 import path from 'path'
-import { route } from '../../shared/route/index.js'
+import { route } from '../../shared/route/index'
 import {
   assert,
   assertUsage,
@@ -26,7 +26,7 @@ import {
   PLimit,
   isArray,
   changeEnumerable
-} from './utils.js'
+} from './utils'
 import {
   prerenderPage,
   prerender404Page,
@@ -34,45 +34,45 @@ import {
   type RenderContext,
   getPageContextInitEnhanced,
   PageContextInitEnhanced
-} from '../runtime/renderPage/renderPageAlreadyRouted.js'
+} from '../runtime/renderPage/renderPageAlreadyRouted'
 import pc from '@brillout/picocolors'
 import { cpus } from 'os'
-import type { PageFile } from '../../shared/getPageFiles.js'
+import type { PageFile } from '../../shared/getPageFiles'
 import {
   getGlobalContext,
   initGlobalContext_runPrerender,
   setGlobalContext_isPrerendering
-} from '../runtime/globalContext.js'
+} from '../runtime/globalContext'
 import { resolveConfig } from 'vite'
-import { getConfigVike } from '../shared/getConfigVike.js'
+import { getConfigVike } from '../shared/getConfigVike'
 import type { InlineConfig } from 'vite'
-import { getPageFilesServerSide } from '../../shared/getPageFiles.js'
-import { getPageContextRequestUrl } from '../../shared/getPageContextRequestUrl.js'
-import { getUrlFromRouteString } from '../../shared/route/resolveRouteString.js'
-import { getConfigValueFilePathToShowToUser } from '../../shared/page-configs/helpers.js'
-import { getConfigValueRuntime } from '../../shared/page-configs/getConfigValue.js'
-import { loadConfigValues } from '../../shared/page-configs/loadConfigValues.js'
-import { isErrorPage } from '../../shared/error-page.js'
+import { getPageFilesServerSide } from '../../shared/getPageFiles'
+import { getPageContextRequestUrl } from '../../shared/getPageContextRequestUrl'
+import { getUrlFromRouteString } from '../../shared/route/resolveRouteString'
+import { getConfigValueFilePathToShowToUser } from '../../shared/page-configs/helpers'
+import { getConfigValueRuntime } from '../../shared/page-configs/getConfigValue'
+import { loadConfigValues } from '../../shared/page-configs/loadConfigValues'
+import { isErrorPage } from '../../shared/error-page'
 import {
   getPageContextUrlComputed,
   PageContextUrlInternal,
   PageContextUrlSource
-} from '../../shared/getPageContextUrlComputed.js'
-import { isAbortError } from '../../shared/route/abort.js'
-import { loadUserFilesServerSide } from '../runtime/renderPage/loadUserFilesServerSide.js'
+} from '../../shared/getPageContextUrlComputed'
+import { isAbortError } from '../../shared/route/abort'
+import { loadUserFilesServerSide } from '../runtime/renderPage/loadUserFilesServerSide'
 import {
   getHookFromPageConfig,
   getHookFromPageConfigGlobal,
   getHookTimeoutDefault,
   getHook_setIsPrerenderering
-} from '../../shared/hooks/getHook.js'
-import { noRouteMatch } from '../../shared/route/noRouteMatch.js'
-import type { PageConfigBuildTime } from '../../shared/page-configs/PageConfig.js'
-import { getVikeConfig } from '../plugin/plugins/importUserCode/v1-design/getVikeConfig.js'
-import type { HookTimeout } from '../../shared/hooks/getHook.js'
-import { logErrorHint } from '../runtime/renderPage/logErrorHint.js'
-import { executeHook, isUserHookError } from '../../shared/hooks/executeHook.js'
-import { getConfigValueBuildTime } from '../../shared/page-configs/getConfigValueBuildTime.js'
+} from '../../shared/hooks/getHook'
+import { noRouteMatch } from '../../shared/route/noRouteMatch'
+import type { PageConfigBuildTime } from '../../shared/page-configs/PageConfig'
+import { getVikeConfig } from '../plugin/plugins/importUserCode/v1-design/getVikeConfig'
+import type { HookTimeout } from '../../shared/hooks/getHook'
+import { logErrorHint } from '../runtime/renderPage/logErrorHint'
+import { executeHook, isUserHookError } from '../../shared/hooks/executeHook'
+import { getConfigValueBuildTime } from '../../shared/page-configs/getConfigValueBuildTime'
 
 type HtmlFile = {
   urlOriginal: string
diff --git a/vike/node/prerender/utils.ts b/vike/node/prerender/utils.ts
index b80fc4a3ee..1317d42d12 100644
--- a/vike/node/prerender/utils.ts
+++ b/vike/node/prerender/utils.ts
@@ -1,19 +1,19 @@
-import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser.js'
+import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser'
 assertIsNotBrowser()
 
-export * from '../../utils/assert.js'
-export * from '../../utils/hasProp.js'
-export * from '../../utils/projectInfo.js'
-export * from '../../utils/objectAssign.js'
-export * from '../../utils/isObjectWithKeys.js'
-export * from '../../utils/isCallable.js'
-export * from '../../utils/getOutDirs.js'
-export * from '../../utils/isPropertyGetter.js'
-export * from '../../utils/filesystemPathHandling.js'
-export * from '../../utils/urlToFile.js'
-export * from '../../utils/isPlainObject.js'
-export * from '../../utils/assertNodeEnv.js'
-export * from '../../utils/pLimit.js'
-export * from '../../utils/isFilePathAbsoluteFilesystem.js'
-export * from '../../utils/isArray.js'
-export * from '../../utils/changeEnumerable.js'
+export * from '../../utils/assert'
+export * from '../../utils/hasProp'
+export * from '../../utils/projectInfo'
+export * from '../../utils/objectAssign'
+export * from '../../utils/isObjectWithKeys'
+export * from '../../utils/isCallable'
+export * from '../../utils/getOutDirs'
+export * from '../../utils/isPropertyGetter'
+export * from '../../utils/filesystemPathHandling'
+export * from '../../utils/urlToFile'
+export * from '../../utils/isPlainObject'
+export * from '../../utils/assertNodeEnv'
+export * from '../../utils/pLimit'
+export * from '../../utils/isFilePathAbsoluteFilesystem'
+export * from '../../utils/isArray'
+export * from '../../utils/changeEnumerable'
diff --git a/vike/node/runtime/globalContext.ts b/vike/node/runtime/globalContext.ts
index 28c1987e05..f1b9d9a619 100644
--- a/vike/node/runtime/globalContext.ts
+++ b/vike/node/runtime/globalContext.ts
@@ -25,17 +25,17 @@ import {
   objectAssign,
   objectKeys,
   genPromise
-} from './utils.js'
-import type { ViteManifest } from '../shared/ViteManifest.js'
+} from './utils'
+import type { ViteManifest } from '../shared/ViteManifest'
 import type { ResolvedConfig, ViteDevServer } from 'vite'
-import { loadImportBuild } from './globalContext/loadImportBuild.js'
-import { setPageFiles } from '../../shared/getPageFiles.js'
-import { assertPluginManifest, PluginManifest } from '../shared/assertPluginManifest.js'
-import type { ConfigVikeResolved } from '../../shared/ConfigVike.js'
-import { getConfigVike } from '../shared/getConfigVike.js'
-import { assertRuntimeManifest, type RuntimeManifest } from '../shared/assertRuntimeManifest.js'
+import { loadImportBuild } from './globalContext/loadImportBuild'
+import { setPageFiles } from '../../shared/getPageFiles'
+import { assertPluginManifest, PluginManifest } from '../shared/assertPluginManifest'
+import type { ConfigVikeResolved } from '../../shared/ConfigVike'
+import { getConfigVike } from '../shared/getConfigVike'
+import { assertRuntimeManifest, type RuntimeManifest } from '../shared/assertRuntimeManifest'
 import pc from '@brillout/picocolors'
-import { getPageFilesExports } from './page-files/getPageFilesExports.js'
+import { getPageFilesExports } from './page-files/getPageFilesExports'
 const globalObject = getGlobalObject<{
   globalContext?: GlobalContext
   viteDevServer?: ViteDevServer
diff --git a/vike/node/runtime/globalContext/loadImportBuild.ts b/vike/node/runtime/globalContext/loadImportBuild.ts
index c742a979fc..55f3c2b5df 100644
--- a/vike/node/runtime/globalContext/loadImportBuild.ts
+++ b/vike/node/runtime/globalContext/loadImportBuild.ts
@@ -2,7 +2,7 @@ export { loadImportBuild }
 export { setImportBuildGetters }
 
 import { importServerProductionEntry } from '@brillout/vite-plugin-server-entry/runtime'
-import { assert } from '../utils.js'
+import { assert } from '../utils'
 
 const buildGetters = (globalThis.__vike_buildGetters = globalThis.__vike_buildGetters || {
   getters: null
diff --git a/vike/node/runtime/html/injectAssets.ts b/vike/node/runtime/html/injectAssets.ts
index 625a15dbb9..d3d6510fe6 100644
--- a/vike/node/runtime/html/injectAssets.ts
+++ b/vike/node/runtime/html/injectAssets.ts
@@ -3,21 +3,21 @@ export { injectHtmlTagsToStream }
 export type { PageContextInjectAssets }
 export type { PageContextPromise }
 
-import { assert, isCallable, isPromise } from '../utils.js'
-import type { PageAsset } from '../renderPage/getPageAssets.js'
-import { assertPageContextProvidedByUser } from '../../../shared/assertPageContextProvidedByUser.js'
+import { assert, isCallable, isPromise } from '../utils'
+import type { PageAsset } from '../renderPage/getPageAssets'
+import { assertPageContextProvidedByUser } from '../../../shared/assertPageContextProvidedByUser'
 import {
   joinHtmlTags,
   injectHtmlTags,
   createHtmlHeadIfMissing,
   injectHtmlTagsUsingStream
-} from './injectAssets/injectHtmlTags.js'
-import type { HtmlPart } from './renderHtml.js'
-import { getHtmlTags, type PreloadFilter, type HtmlTag } from './injectAssets/getHtmlTags.js'
-import type { StreamFromReactStreamingPackage } from './stream/react-streaming.js'
-import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig.js'
-import type { PageContextSerialization } from './serializePageContextClientSide.js'
-import { getViteDevScript } from './injectAssets/getViteDevScript.js'
+} from './injectAssets/injectHtmlTags'
+import type { HtmlPart } from './renderHtml'
+import { getHtmlTags, type PreloadFilter, type HtmlTag } from './injectAssets/getHtmlTags'
+import type { StreamFromReactStreamingPackage } from './stream/react-streaming'
+import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig'
+import type { PageContextSerialization } from './serializePageContextClientSide'
+import { getViteDevScript } from './injectAssets/getViteDevScript'
 
 type PageContextInjectAssets = {
   urlPathname: string
diff --git a/vike/node/runtime/html/injectAssets/getHtmlTags.ts b/vike/node/runtime/html/injectAssets/getHtmlTags.ts
index d7a6cb8873..c9911f588f 100644
--- a/vike/node/runtime/html/injectAssets/getHtmlTags.ts
+++ b/vike/node/runtime/html/injectAssets/getHtmlTags.ts
@@ -3,20 +3,20 @@ export type { HtmlTag }
 export type { PreloadFilter }
 export type { InjectFilterEntry }
 
-import { assert, assertWarning, assertUsage, isObject, freezePartial } from '../../utils.js'
-import { type PageContextSerialization, serializePageContextClientSide } from '../serializePageContextClientSide.js'
-import { sanitizeJson } from './sanitizeJson.js'
-import { inferAssetTag, inferPreloadTag } from './inferHtmlTags.js'
-import { mergeScriptTags } from './mergeScriptTags.js'
-import type { PageContextInjectAssets } from '../injectAssets.js'
-import type { StreamFromReactStreamingPackage } from '../stream/react-streaming.js'
-import type { PageAsset } from '../../renderPage/getPageAssets.js'
-import type { PageConfigRuntime } from '../../../../shared/page-configs/PageConfig.js'
-import { getPageConfig } from '../../../../shared/page-configs/helpers.js'
-import { getConfigValueRuntime } from '../../../../shared/page-configs/getConfigValue.js'
-import { getGlobalContext } from '../../globalContext.js'
+import { assert, assertWarning, assertUsage, isObject, freezePartial } from '../../utils'
+import { type PageContextSerialization, serializePageContextClientSide } from '../serializePageContextClientSide'
+import { sanitizeJson } from './sanitizeJson'
+import { inferAssetTag, inferPreloadTag } from './inferHtmlTags'
+import { mergeScriptTags } from './mergeScriptTags'
+import type { PageContextInjectAssets } from '../injectAssets'
+import type { StreamFromReactStreamingPackage } from '../stream/react-streaming'
+import type { PageAsset } from '../../renderPage/getPageAssets'
+import type { PageConfigRuntime } from '../../../../shared/page-configs/PageConfig'
+import { getPageConfig } from '../../../../shared/page-configs/helpers'
+import { getConfigValueRuntime } from '../../../../shared/page-configs/getConfigValue'
+import { getGlobalContext } from '../../globalContext'
 import pc from '@brillout/picocolors'
-import { getConfigDefinedAt } from '../../../../shared/page-configs/getConfigDefinedAt.js'
+import { getConfigDefinedAt } from '../../../../shared/page-configs/getConfigDefinedAt'
 
 const stamp = '__injectFilterEntry'
 
diff --git a/vike/node/runtime/html/injectAssets/getViteDevScript.ts b/vike/node/runtime/html/injectAssets/getViteDevScript.ts
index a0827e53b5..25f4083563 100644
--- a/vike/node/runtime/html/injectAssets/getViteDevScript.ts
+++ b/vike/node/runtime/html/injectAssets/getViteDevScript.ts
@@ -1,7 +1,7 @@
 export { getViteDevScript }
 
-import { getGlobalContext } from '../../globalContext.js'
-import { assert, assertUsage, assertWarning } from '../../utils.js'
+import { getGlobalContext } from '../../globalContext'
+import { assert, assertUsage, assertWarning } from '../../utils'
 import pc from '@brillout/picocolors'
 
 async function getViteDevScript(): Promise<string> {
diff --git a/vike/node/runtime/html/injectAssets/inferHtmlTags.ts b/vike/node/runtime/html/injectAssets/inferHtmlTags.ts
index d4ab674a73..0c4418024f 100644
--- a/vike/node/runtime/html/injectAssets/inferHtmlTags.ts
+++ b/vike/node/runtime/html/injectAssets/inferHtmlTags.ts
@@ -3,8 +3,8 @@ export { inferPreloadTag }
 export { inferEarlyHintLink }
 export { scriptAttrs }
 
-import { assert } from '../../utils.js'
-import type { PageAsset } from '../../renderPage/getPageAssets.js'
+import { assert } from '../../utils'
+import type { PageAsset } from '../../renderPage/getPageAssets'
 
 // We can't use `defer` here. With `defer`, the entry script won't start before `</body>` has been parsed, preventing progressive hydration during SSR streaming, see https://github.com/vikejs/vike/pull/1271
 const scriptAttrs = 'type="module" async'
diff --git a/vike/node/runtime/html/injectAssets/injectAssets__public.ts b/vike/node/runtime/html/injectAssets/injectAssets__public.ts
index 5467acdc43..dcb938dabb 100644
--- a/vike/node/runtime/html/injectAssets/injectAssets__public.ts
+++ b/vike/node/runtime/html/injectAssets/injectAssets__public.ts
@@ -1,8 +1,8 @@
 export { injectAssets__public }
 
-import { assertUsage, assertWarning, castProp, hasProp } from '../../utils.js'
-import { injectHtmlTagsToString } from '../injectAssets.js'
-import type { PageAsset } from '../../renderPage/getPageAssets.js'
+import { assertUsage, assertWarning, castProp, hasProp } from '../../utils'
+import { injectHtmlTagsToString } from '../injectAssets'
+import type { PageAsset } from '../../renderPage/getPageAssets'
 
 // TODO/v1-release: remove
 async function injectAssets__public(htmlString: string, pageContext: Record<string, unknown>): Promise<string> {
diff --git a/vike/node/runtime/html/injectAssets/injectHtmlTags.spec.ts b/vike/node/runtime/html/injectAssets/injectHtmlTags.spec.ts
index 36cb6dc6f8..72e17080f1 100644
--- a/vike/node/runtime/html/injectAssets/injectHtmlTags.spec.ts
+++ b/vike/node/runtime/html/injectAssets/injectHtmlTags.spec.ts
@@ -1,4 +1,4 @@
-import { injectAtOpeningTag, injectAtClosingTag } from './injectHtmlTags.js'
+import { injectAtOpeningTag, injectAtClosingTag } from './injectHtmlTags'
 import { expect, describe, it } from 'vitest'
 
 const htmlHead1 = '<html><head></head></html>'
diff --git a/vike/node/runtime/html/injectAssets/injectHtmlTags.ts b/vike/node/runtime/html/injectAssets/injectHtmlTags.ts
index c9562f6095..df2fb9f801 100644
--- a/vike/node/runtime/html/injectAssets/injectHtmlTags.ts
+++ b/vike/node/runtime/html/injectAssets/injectHtmlTags.ts
@@ -9,9 +9,9 @@ export { joinHtmlTags }
 export { injectAtOpeningTag }
 export { injectAtClosingTag }
 
-import { assert, assertUsage, slice } from '../../utils.js'
-import type { StreamFromReactStreamingPackage } from '../stream/react-streaming.js'
-import type { HtmlTag } from './getHtmlTags.js'
+import { assert, assertUsage, slice } from '../../utils'
+import type { StreamFromReactStreamingPackage } from '../stream/react-streaming'
+import type { HtmlTag } from './getHtmlTags'
 
 type Position = 'HTML_BEGIN' | 'HTML_END'
 function injectHtmlTags(htmlString: string, htmlTags: HtmlTag[], position: Position): string {
diff --git a/vike/node/runtime/html/injectAssets/mergeScriptTags.ts b/vike/node/runtime/html/injectAssets/mergeScriptTags.ts
index d07ba6c5ba..d1ae71858c 100644
--- a/vike/node/runtime/html/injectAssets/mergeScriptTags.ts
+++ b/vike/node/runtime/html/injectAssets/mergeScriptTags.ts
@@ -1,7 +1,7 @@
 export { mergeScriptTags }
 
-import { assert } from '../../utils.js'
-import { scriptAttrs } from './inferHtmlTags.js'
+import { assert } from '../../utils'
+import { scriptAttrs } from './inferHtmlTags'
 
 const scriptRE = /(<script\b(?:\s[^>]*>|>))(.*?)<\/script>/gims
 const srcRE = /\bsrc\s*=\s*(?:"([^"]+)"|'([^']+)'|([^\s'">]+))/im
diff --git a/vike/node/runtime/html/renderHtml.ts b/vike/node/runtime/html/renderHtml.ts
index 1c7ec747bc..1e0981a123 100644
--- a/vike/node/runtime/html/renderHtml.ts
+++ b/vike/node/runtime/html/renderHtml.ts
@@ -19,9 +19,9 @@ import {
   isHtml,
   isPromise,
   objectAssign
-} from '../utils.js'
-import { injectHtmlTagsToString, injectHtmlTagsToStream } from './injectAssets.js'
-import type { PageContextInjectAssets } from './injectAssets.js'
+} from '../utils'
+import { injectHtmlTagsToString, injectHtmlTagsToStream } from './injectAssets'
+import type { PageContextInjectAssets } from './injectAssets'
 import {
   processStream,
   isStream,
@@ -29,12 +29,12 @@ import {
   streamToString,
   StreamTypePatch,
   StreamProviderNormalized
-} from './stream.js'
-import { isStreamFromReactStreamingPackage } from './stream/react-streaming.js'
-import type { StreamFromReactStreamingPackage } from './stream/react-streaming.js'
-import type { PageAsset } from '../renderPage/getPageAssets.js'
-import type { PreloadFilter } from './injectAssets/getHtmlTags.js'
-import { getGlobalContext } from '../globalContext.js'
+} from './stream'
+import { isStreamFromReactStreamingPackage } from './stream/react-streaming'
+import type { StreamFromReactStreamingPackage } from './stream/react-streaming'
+import type { PageAsset } from '../renderPage/getPageAssets'
+import type { PreloadFilter } from './injectAssets/getHtmlTags'
+import { getGlobalContext } from '../globalContext'
 import pc from '@brillout/picocolors'
 
 type DocumentHtml = TemplateWrapped | EscapedString | StreamProviderAny
diff --git a/vike/node/runtime/html/serializePageContextClientSide.ts b/vike/node/runtime/html/serializePageContextClientSide.ts
index b536606e1c..5d3039aecf 100644
--- a/vike/node/runtime/html/serializePageContextClientSide.ts
+++ b/vike/node/runtime/html/serializePageContextClientSide.ts
@@ -3,15 +3,15 @@ export { serializePageContextAbort }
 export type { PageContextSerialization }
 
 import { stringify, isJsonSerializerError } from '@brillout/json-serializer/stringify'
-import { assert, assertUsage, assertWarning, getPropAccessNotation, hasProp, unique } from '../utils.js'
-import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig.js'
-import { isErrorPage } from '../../../shared/error-page.js'
-import { addIs404ToPageProps } from '../../../shared/addIs404ToPageProps.js'
+import { assert, assertUsage, assertWarning, getPropAccessNotation, hasProp, unique } from '../utils'
+import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig'
+import { isErrorPage } from '../../../shared/error-page'
+import { addIs404ToPageProps } from '../../../shared/addIs404ToPageProps'
 import pc from '@brillout/picocolors'
-import { notSerializable } from '../../../shared/notSerializable.js'
-import type { UrlRedirect } from '../../../shared/route/abort.js'
-import { pageContextInitIsPassedToClient } from '../../../shared/misc/pageContextInitIsPassedToClient.js'
-import { isServerSideError } from '../../../shared/misc/isServerSideError.js'
+import { notSerializable } from '../../../shared/notSerializable'
+import type { UrlRedirect } from '../../../shared/route/abort'
+import { pageContextInitIsPassedToClient } from '../../../shared/misc/pageContextInitIsPassedToClient'
+import { isServerSideError } from '../../../shared/misc/isServerSideError'
 
 const PASS_TO_CLIENT: string[] = [
   'abortReason',
diff --git a/vike/node/runtime/html/stream.ts b/vike/node/runtime/html/stream.ts
index fa9f4244cb..2a674ddf4c 100644
--- a/vike/node/runtime/html/stream.ts
+++ b/vike/node/runtime/html/stream.ts
@@ -41,14 +41,14 @@ import {
   isCallable,
   createDebugger,
   isBug
-} from '../utils.js'
-import { HtmlRender } from './renderHtml.js'
+} from '../utils'
+import { HtmlRender } from './renderHtml'
 import {
   getStreamOfReactStreamingPackage,
   isStreamFromReactStreamingPackage,
   StreamFromReactStreamingPackagePublic,
   streamFromReactStreamingPackageToString
-} from './stream/react-streaming.js'
+} from './stream/react-streaming'
 import { import_ } from '@brillout/import'
 import type { Readable as Readable_, Writable as Writable_ } from 'node:stream'
 import pc from '@brillout/picocolors'
diff --git a/vike/node/runtime/html/stream/react-streaming.ts b/vike/node/runtime/html/stream/react-streaming.ts
index 824d711533..2e2351f10e 100644
--- a/vike/node/runtime/html/stream/react-streaming.ts
+++ b/vike/node/runtime/html/stream/react-streaming.ts
@@ -7,8 +7,8 @@ export type { StreamFromReactStreamingPackage }
 export type { StreamFromReactStreamingPackagePublic }
 
 import type { renderToStream } from 'react-streaming/server'
-import { assert, assertUsage, hasProp, isVikeReactApp } from '../../utils.js'
-import { streamPipeNodeToString, StreamReadableWeb, streamReadableWebToString, StreamWritableNode } from '../stream.js'
+import { assert, assertUsage, hasProp, isVikeReactApp } from '../../utils'
+import { streamPipeNodeToString, StreamReadableWeb, streamReadableWebToString, StreamWritableNode } from '../stream'
 
 // We use this simplistic public type to avoid type mismatches (when the user installed another version than Vike's devDependency#react-streaming install).
 type StreamFromReactStreamingPackagePublic = { injectToStream: Function }
diff --git a/vike/node/runtime/index-common.ts b/vike/node/runtime/index-common.ts
index 1382cbe997..87c13634db 100644
--- a/vike/node/runtime/index-common.ts
+++ b/vike/node/runtime/index-common.ts
@@ -1,17 +1,17 @@
-export { renderPage } from './renderPage.js'
-export { escapeInject, dangerouslySkipEscape } from './html/renderHtml.js'
-export { pipeWebStream, pipeNodeStream, pipeStream, stampPipe } from './html/stream.js'
-export { PROJECT_VERSION as version } from './utils.js'
-export { getGlobalContextSync, getGlobalContextAsync } from './globalContext.js'
+export { renderPage } from './renderPage'
+export { escapeInject, dangerouslySkipEscape } from './html/renderHtml'
+export { pipeWebStream, pipeNodeStream, pipeStream, stampPipe } from './html/stream'
+export { PROJECT_VERSION as version } from './utils'
+export { getGlobalContextSync, getGlobalContextAsync } from './globalContext'
 
 // TODO/v1-release: remove
-export { injectAssets__public as _injectAssets } from './html/injectAssets/injectAssets__public.js'
+export { injectAssets__public as _injectAssets } from './html/injectAssets/injectAssets__public'
 // TODO/v1-release: remove
-export { createPageRenderer } from '../createPageRenderer.js'
+export { createPageRenderer } from '../createPageRenderer'
 
 addEcosystemStamp()
 
-import './page-files/setup.js'
+import './page-files/setup'
 
 // Used by:
 // - Telefunc (to detect the user's stack https://github.com/brillout/telefunc/blob/8288310e88e06a42b710d39c39fb502364ca6d30/telefunc/utils/isVikeApp.ts#L4)
diff --git a/vike/node/runtime/index-deprecated.ts b/vike/node/runtime/index-deprecated.ts
index ee84857e2e..d1019db593 100644
--- a/vike/node/runtime/index-deprecated.ts
+++ b/vike/node/runtime/index-deprecated.ts
@@ -1,21 +1,21 @@
 // TODO/v1-release: replace this with:
 // assertUsage(false, "`import { something } from 'vike'` doesn't exist: instead import from 'vike/server', 'vike/client', 'vike/plugin', ...")
 
-import { isBrowser } from '../../utils/isBrowser.js'
-import { assertUsage } from '../../utils/assert.js'
+import { isBrowser } from '../../utils/isBrowser'
+import { assertUsage } from '../../utils/assert'
 assertUsage(
   !isBrowser(),
   "It's forbidden to `import { something } from 'vike'` on the client-side: the module 'vike' is a server-only module.",
   { showStackTrace: true }
 )
 
-export * from './index-common.js'
-export * from '../../types/index-dreprecated.js'
+export * from './index-common'
+export * from '../../types/index-dreprecated'
 
-import { assertWarning } from './utils.js'
+import { assertWarning } from './utils'
 import pc from '@brillout/picocolors'
 
-import { RenderErrorPage as RenderErrorPage_ } from '../../shared/route/abort.js'
+import { RenderErrorPage as RenderErrorPage_ } from '../../shared/route/abort'
 /** @deprecated
  * Replace:
  *   ```
diff --git a/vike/node/runtime/index.ts b/vike/node/runtime/index.ts
index e5d4264b7b..646f972f1e 100644
--- a/vike/node/runtime/index.ts
+++ b/vike/node/runtime/index.ts
@@ -1,9 +1,9 @@
-import { isBrowser } from '../../utils/isBrowser.js'
-import { assertUsage } from '../../utils/assert.js'
+import { isBrowser } from '../../utils/isBrowser'
+import { assertUsage } from '../../utils/assert'
 assertUsage(
   !isBrowser(),
   "It's forbidden to `import { something } from 'vike/server'` on the client-side: the module 'vike/server' is a server-only module.",
   { showStackTrace: true }
 )
 
-export * from './index-common.js'
+export * from './index-common'
diff --git a/vike/node/runtime/onLoad.ts b/vike/node/runtime/onLoad.ts
index faea70b9d7..256b3f92e3 100644
--- a/vike/node/runtime/onLoad.ts
+++ b/vike/node/runtime/onLoad.ts
@@ -1,10 +1,10 @@
 export { onLoad }
 
-import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser.js'
-import { assertNodeVersion } from '../../utils/assertNodeVersion.js'
+import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser'
+import { assertNodeVersion } from '../../utils/assertNodeVersion'
 import { installRequireShim } from '@brillout/require-shim'
-import { setAlwaysShowStackTrace } from './utils.js'
-import { isErrorDebug } from '../shared/isErrorDebug.js'
+import { setAlwaysShowStackTrace } from './utils'
+import { isErrorDebug } from '../shared/isErrorDebug'
 
 function onLoad() {
   assertIsNotBrowser()
diff --git a/vike/node/runtime/page-files/getPageFilesExports.ts b/vike/node/runtime/page-files/getPageFilesExports.ts
index 8e3af61099..e838f5ffa6 100644
--- a/vike/node/runtime/page-files/getPageFilesExports.ts
+++ b/vike/node/runtime/page-files/getPageFilesExports.ts
@@ -1,8 +1,8 @@
 export { getPageFilesExports }
 
-import { assert, debugGlob, isObject } from '../utils.js'
-import { getViteDevServer } from '../globalContext.js'
-import { virtualFileIdImportUserCodeServer } from '../../shared/virtual-files/virtualFileImportUserCode.js'
+import { assert, debugGlob, isObject } from '../utils'
+import { getViteDevServer } from '../globalContext'
+import { virtualFileIdImportUserCodeServer } from '../../shared/virtual-files/virtualFileImportUserCode'
 
 async function getPageFilesExports(): Promise<Record<string, unknown>> {
   const viteDevServer = getViteDevServer()
diff --git a/vike/node/runtime/page-files/setup.ts b/vike/node/runtime/page-files/setup.ts
index f0d6a2b230..0048f5f785 100644
--- a/vike/node/runtime/page-files/setup.ts
+++ b/vike/node/runtime/page-files/setup.ts
@@ -1,4 +1,4 @@
-import { setPageFilesAsync } from '../../../shared/getPageFiles.js'
-import { getPageFilesExports } from './getPageFilesExports.js'
+import { setPageFilesAsync } from '../../../shared/getPageFiles'
+import { getPageFilesExports } from './getPageFilesExports'
 
 setPageFilesAsync(getPageFilesExports)
diff --git a/vike/node/runtime/renderPage.ts b/vike/node/runtime/renderPage.ts
index 8a2d145f83..17138f40fb 100644
--- a/vike/node/runtime/renderPage.ts
+++ b/vike/node/runtime/renderPage.ts
@@ -7,8 +7,8 @@ import {
   RenderContext,
   renderPageAlreadyRouted,
   PageContextInitEnhanced
-} from './renderPage/renderPageAlreadyRouted.js'
-import { route } from '../../shared/route/index.js'
+} from './renderPage/renderPageAlreadyRouted'
+import { route } from '../../shared/route/index'
 import {
   assert,
   hasProp,
@@ -30,7 +30,7 @@ import {
   isUri,
   type UrlPublic,
   getUrlPretty
-} from './utils.js'
+} from './utils'
 import {
   assertNoInfiniteAbortLoop,
   ErrorAbort,
@@ -38,32 +38,32 @@ import {
   isAbortError,
   logAbortErrorHandled,
   PageContextFromRewrite
-} from '../../shared/route/abort.js'
-import { getGlobalContext, initGlobalContext_renderPage } from './globalContext.js'
-import { handlePageContextRequestUrl } from './renderPage/handlePageContextRequestUrl.js'
+} from '../../shared/route/abort'
+import { getGlobalContext, initGlobalContext_renderPage } from './globalContext'
+import { handlePageContextRequestUrl } from './renderPage/handlePageContextRequestUrl'
 import {
   createHttpResponseFavicon404,
   createHttpResponseRedirect,
   createHttpResponsePageContextJson,
   HttpResponse,
   createHttpResponseError
-} from './renderPage/createHttpResponse.js'
-import { logRuntimeError, logRuntimeInfo } from './renderPage/loggerRuntime.js'
-import { isNewError } from './renderPage/isNewError.js'
-import { assertArguments } from './renderPage/assertArguments.js'
-import type { PageContextDebugRouteMatches } from './renderPage/debugPageFiles.js'
-import { log404 } from './renderPage/log404/index.js'
-import { isConfigInvalid } from './renderPage/isConfigInvalid.js'
+} from './renderPage/createHttpResponse'
+import { logRuntimeError, logRuntimeInfo } from './renderPage/loggerRuntime'
+import { isNewError } from './renderPage/isNewError'
+import { assertArguments } from './renderPage/assertArguments'
+import type { PageContextDebugRouteMatches } from './renderPage/debugPageFiles'
+import { log404 } from './renderPage/log404/index'
+import { isConfigInvalid } from './renderPage/isConfigInvalid'
 import pc from '@brillout/picocolors'
-import type { PageContextServer } from '../../types/index.js'
-import { serializePageContextAbort, serializePageContextClientSide } from './html/serializePageContextClientSide.js'
-import { getErrorPageId } from '../../shared/error-page.js'
-import { handleErrorWithoutErrorPage } from './renderPage/handleErrorWithoutErrorPage.js'
-import { loadUserFilesServerSide } from './renderPage/loadUserFilesServerSide.js'
-import { resolveRedirects } from './renderPage/resolveRedirects.js'
-import { PageContextBuiltInServerInternal } from '../../shared/types.js'
-import type { PageFile } from '../../shared/getPageFiles.js'
-import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig.js'
+import type { PageContextServer } from '../../types/index'
+import { serializePageContextAbort, serializePageContextClientSide } from './html/serializePageContextClientSide'
+import { getErrorPageId } from '../../shared/error-page'
+import { handleErrorWithoutErrorPage } from './renderPage/handleErrorWithoutErrorPage'
+import { loadUserFilesServerSide } from './renderPage/loadUserFilesServerSide'
+import { resolveRedirects } from './renderPage/resolveRedirects'
+import { PageContextBuiltInServerInternal } from '../../shared/types'
+import type { PageFile } from '../../shared/getPageFiles'
+import type { PageConfigRuntime } from '../../shared/page-configs/PageConfig'
 
 const globalObject = getGlobalObject('runtime/renderPage.ts', {
   httpRequestsCount: 0
diff --git a/vike/node/runtime/renderPage/analyzePage.ts b/vike/node/runtime/renderPage/analyzePage.ts
index 686418090b..9be33c3c2c 100644
--- a/vike/node/runtime/renderPage/analyzePage.ts
+++ b/vike/node/runtime/renderPage/analyzePage.ts
@@ -1,14 +1,14 @@
 export { analyzePage }
 
-import type { ClientDependency } from '../../../shared/getPageFiles/analyzePageClientSide/ClientDependency.js'
-import { getVikeClientEntry } from '../../../shared/getPageFiles/analyzePageClientSide/determineClientEntry.js'
-import type { PageFile } from '../../../shared/getPageFiles/getPageFileObject.js'
-import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig.js'
-import { type AnalysisResult, analyzePageClientSide } from '../../../shared/getPageFiles/analyzePageClientSide.js'
-import { getVirtualFileIdPageConfigValuesAll } from '../../shared/virtual-files/virtualFilePageConfigValuesAll.js'
-import { analyzeClientSide } from '../../../shared/getPageFiles/analyzeClientSide.js'
-import { getGlobalContext } from '../globalContext.js'
-import { getConfigValueRuntime } from '../../../shared/page-configs/getConfigValue.js'
+import type { ClientDependency } from '../../../shared/getPageFiles/analyzePageClientSide/ClientDependency'
+import { getVikeClientEntry } from '../../../shared/getPageFiles/analyzePageClientSide/determineClientEntry'
+import type { PageFile } from '../../../shared/getPageFiles/getPageFileObject'
+import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig'
+import { type AnalysisResult, analyzePageClientSide } from '../../../shared/getPageFiles/analyzePageClientSide'
+import { getVirtualFileIdPageConfigValuesAll } from '../../shared/virtual-files/virtualFilePageConfigValuesAll'
+import { analyzeClientSide } from '../../../shared/getPageFiles/analyzeClientSide'
+import { getGlobalContext } from '../globalContext'
+import { getConfigValueRuntime } from '../../../shared/page-configs/getConfigValue'
 
 function analyzePage(pageFilesAll: PageFile[], pageConfig: null | PageConfigRuntime, pageId: string): AnalysisResult {
   if (pageConfig) {
diff --git a/vike/node/runtime/renderPage/assertArguments.ts b/vike/node/runtime/renderPage/assertArguments.ts
index cc40722847..86396ecb32 100644
--- a/vike/node/runtime/renderPage/assertArguments.ts
+++ b/vike/node/runtime/renderPage/assertArguments.ts
@@ -1,6 +1,6 @@
 export { assertArguments }
 
-import { assert, assertUsage, assertWarning, hasProp, isObject } from '../utils.js'
+import { assert, assertUsage, assertWarning, hasProp, isObject } from '../utils'
 import pc from '@brillout/picocolors'
 
 function assertArguments(...args: unknown[]): void {
diff --git a/vike/node/runtime/renderPage/createHttpResponse.ts b/vike/node/runtime/renderPage/createHttpResponse.ts
index fb34774f68..2d5170aefd 100644
--- a/vike/node/runtime/renderPage/createHttpResponse.ts
+++ b/vike/node/runtime/renderPage/createHttpResponse.ts
@@ -5,18 +5,18 @@ export { createHttpResponseRedirect }
 export { createHttpResponseFavicon404 }
 export type { HttpResponse }
 
-import type { GetPageAssets } from './getPageAssets.js'
-import { assert, assertWarning, escapeHtml } from '../utils.js'
-import type { HtmlRender } from '../html/renderHtml.js'
-import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig.js'
-import { getErrorPageId, isErrorPage } from '../../../shared/error-page.js'
-import type { RenderHook } from './executeOnRenderHtmlHook.js'
-import type { RedirectStatusCode, AbortStatusCode, UrlRedirect } from '../../../shared/route/abort.js'
-import { getHttpResponseBody, getHttpResponseBodyStreamHandlers, HttpResponseBody } from './getHttpResponseBody.js'
-import { getEarlyHints, type EarlyHint } from './getEarlyHints.js'
-import { getCacheControl } from './createHttpResponse/getCacheControl.js'
-import { assertNoInfiniteHttpRedirect } from './createHttpResponse/assertNoInfiniteHttpRedirect.js'
-import type { PageFile } from '../../../shared/getPageFiles.js'
+import type { GetPageAssets } from './getPageAssets'
+import { assert, assertWarning, escapeHtml } from '../utils'
+import type { HtmlRender } from '../html/renderHtml'
+import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig'
+import { getErrorPageId, isErrorPage } from '../../../shared/error-page'
+import type { RenderHook } from './executeOnRenderHtmlHook'
+import type { RedirectStatusCode, AbortStatusCode, UrlRedirect } from '../../../shared/route/abort'
+import { getHttpResponseBody, getHttpResponseBodyStreamHandlers, HttpResponseBody } from './getHttpResponseBody'
+import { getEarlyHints, type EarlyHint } from './getEarlyHints'
+import { getCacheControl } from './createHttpResponse/getCacheControl'
+import { assertNoInfiniteHttpRedirect } from './createHttpResponse/assertNoInfiniteHttpRedirect'
+import type { PageFile } from '../../../shared/getPageFiles'
 
 type HttpResponse = {
   statusCode: 200 | 404 | 500 | RedirectStatusCode | AbortStatusCode
diff --git a/vike/node/runtime/renderPage/createHttpResponse/assertNoInfiniteHttpRedirect.spec.ts b/vike/node/runtime/renderPage/createHttpResponse/assertNoInfiniteHttpRedirect.spec.ts
index 3daa4fae63..665d1c213f 100644
--- a/vike/node/runtime/renderPage/createHttpResponse/assertNoInfiniteHttpRedirect.spec.ts
+++ b/vike/node/runtime/renderPage/createHttpResponse/assertNoInfiniteHttpRedirect.spec.ts
@@ -1,6 +1,6 @@
 import { expect, describe, it, assert } from 'vitest'
-import { stripAnsi } from '../../utils.js'
-import { assertNoInfiniteHttpRedirect } from './assertNoInfiniteHttpRedirect.js'
+import { stripAnsi } from '../../utils'
+import { assertNoInfiniteHttpRedirect } from './assertNoInfiniteHttpRedirect'
 
 describe('assertNoInfiniteHttpRedirect()', () => {
   it('works', () => {
diff --git a/vike/node/runtime/renderPage/createHttpResponse/assertNoInfiniteHttpRedirect.ts b/vike/node/runtime/renderPage/createHttpResponse/assertNoInfiniteHttpRedirect.ts
index 14b99d7ef9..ac82b1696c 100644
--- a/vike/node/runtime/renderPage/createHttpResponse/assertNoInfiniteHttpRedirect.ts
+++ b/vike/node/runtime/renderPage/createHttpResponse/assertNoInfiniteHttpRedirect.ts
@@ -1,6 +1,6 @@
 export { assertNoInfiniteHttpRedirect }
 
-import { assert, assertUsage, getGlobalObject } from '../../utils.js'
+import { assert, assertUsage, getGlobalObject } from '../../utils'
 import pc from '@brillout/picocolors'
 
 type Graph = Record<string, Set<string>>
diff --git a/vike/node/runtime/renderPage/createHttpResponse/getCacheControl.ts b/vike/node/runtime/renderPage/createHttpResponse/getCacheControl.ts
index 4a27983418..27eeaebf36 100644
--- a/vike/node/runtime/renderPage/createHttpResponse/getCacheControl.ts
+++ b/vike/node/runtime/renderPage/createHttpResponse/getCacheControl.ts
@@ -1,8 +1,8 @@
 export { getCacheControl }
 
-import type { PageConfigRuntime } from '../../../../shared/page-configs/PageConfig.js'
-import { getPageConfig } from '../../../../shared/page-configs/helpers.js'
-import { getConfigValueRuntime } from '../../../../shared/page-configs/getConfigValue.js'
+import type { PageConfigRuntime } from '../../../../shared/page-configs/PageConfig'
+import { getPageConfig } from '../../../../shared/page-configs/helpers'
+import { getConfigValueRuntime } from '../../../../shared/page-configs/getConfigValue'
 
 const defaultValue = 'no-store, max-age=0'
 
diff --git a/vike/node/runtime/renderPage/debugPageFiles.ts b/vike/node/runtime/renderPage/debugPageFiles.ts
index e7f3fd148d..11251b6c90 100644
--- a/vike/node/runtime/renderPage/debugPageFiles.ts
+++ b/vike/node/runtime/renderPage/debugPageFiles.ts
@@ -1,12 +1,12 @@
 export { debugPageFiles }
 export type { PageContextDebugRouteMatches }
 
-import type { RouteMatches } from '../../../shared/route/index.js'
-import type { ClientDependency } from '../../../shared/getPageFiles/analyzePageClientSide/ClientDependency.js'
-import type { PageFile } from '../../../shared/getPageFiles.js'
+import type { RouteMatches } from '../../../shared/route/index'
+import type { ClientDependency } from '../../../shared/getPageFiles/analyzePageClientSide/ClientDependency'
+import type { PageFile } from '../../../shared/getPageFiles'
 import pc from '@brillout/picocolors'
-import { assert, makeFirst, createDebugger } from '../utils.js'
-import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig.js'
+import { assert, makeFirst, createDebugger } from '../utils'
+import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig'
 
 type PageContextDebugRouteMatches = {
   _debugRouteMatches: 'ROUTING_ERROR' | RouteMatches
diff --git a/vike/node/runtime/renderPage/executeOnBeforeRenderAndDataHooks.ts b/vike/node/runtime/renderPage/executeOnBeforeRenderAndDataHooks.ts
index e299b3653d..798a8f5608 100644
--- a/vike/node/runtime/renderPage/executeOnBeforeRenderAndDataHooks.ts
+++ b/vike/node/runtime/renderPage/executeOnBeforeRenderAndDataHooks.ts
@@ -1,13 +1,13 @@
 export { executeOnBeforeRenderAndDataHooks }
 
-import { type PageContextExports } from '../../../shared/getPageFiles.js'
-import { getHook } from '../../../shared/hooks/getHook.js'
+import { type PageContextExports } from '../../../shared/getPageFiles'
+import { getHook } from '../../../shared/hooks/getHook'
 import {
   preparePageContextForUserConsumptionServerSide,
   type PageContextForUserConsumptionServerSide
-} from './preparePageContextForUserConsumptionServerSide.js'
-import { assertOnBeforeRenderHookReturn } from '../../../shared/assertOnBeforeRenderHookReturn.js'
-import { executeHook } from '../../../shared/hooks/executeHook.js'
+} from './preparePageContextForUserConsumptionServerSide'
+import { assertOnBeforeRenderHookReturn } from '../../../shared/assertOnBeforeRenderHookReturn'
+import { executeHook } from '../../../shared/hooks/executeHook'
 
 async function executeOnBeforeRenderAndDataHooks(
   pageContext: {
diff --git a/vike/node/runtime/renderPage/executeOnRenderHtmlHook.ts b/vike/node/runtime/renderPage/executeOnRenderHtmlHook.ts
index 93b706d7a6..9958552930 100644
--- a/vike/node/runtime/renderPage/executeOnRenderHtmlHook.ts
+++ b/vike/node/runtime/renderPage/executeOnRenderHtmlHook.ts
@@ -7,24 +7,24 @@ import {
   renderDocumentHtml,
   DocumentHtml,
   dangerouslySkipEscape
-} from '../html/renderHtml.js'
-import { getHook, type Hook } from '../../../shared/hooks/getHook.js'
-import { assert, assertUsage, assertWarning, isObject, objectAssign, isPromise, isCallable } from '../utils.js'
-import type { PageAsset } from './getPageAssets.js'
-import { isStream } from '../html/stream.js'
-import { assertPageContextProvidedByUser } from '../../../shared/assertPageContextProvidedByUser.js'
-import type { PreloadFilter } from '../html/injectAssets/getHtmlTags.js'
+} from '../html/renderHtml'
+import { getHook, type Hook } from '../../../shared/hooks/getHook'
+import { assert, assertUsage, assertWarning, isObject, objectAssign, isPromise, isCallable } from '../utils'
+import type { PageAsset } from './getPageAssets'
+import { isStream } from '../html/stream'
+import { assertPageContextProvidedByUser } from '../../../shared/assertPageContextProvidedByUser'
+import type { PreloadFilter } from '../html/injectAssets/getHtmlTags'
 import {
   preparePageContextForUserConsumptionServerSide,
   type PageContextForUserConsumptionServerSide
-} from './preparePageContextForUserConsumptionServerSide.js'
-import type { PageContextPromise } from '../html/injectAssets.js'
-import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig.js'
-import { assertHookReturnedObject } from '../../../shared/assertHookReturnedObject.js'
-import { logRuntimeError } from './loggerRuntime.js'
-import type { PageContextSerialization } from '../html/serializePageContextClientSide.js'
+} from './preparePageContextForUserConsumptionServerSide'
+import type { PageContextPromise } from '../html/injectAssets'
+import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig'
+import { assertHookReturnedObject } from '../../../shared/assertHookReturnedObject'
+import { logRuntimeError } from './loggerRuntime'
+import type { PageContextSerialization } from '../html/serializePageContextClientSide'
 import pc from '@brillout/picocolors'
-import { executeHook } from '../../../shared/hooks/executeHook.js'
+import { executeHook } from '../../../shared/hooks/executeHook'
 
 type GetPageAssets = () => Promise<PageAsset[]>
 
diff --git a/vike/node/runtime/renderPage/getEarlyHints.ts b/vike/node/runtime/renderPage/getEarlyHints.ts
index 4e647e4258..f353086333 100644
--- a/vike/node/runtime/renderPage/getEarlyHints.ts
+++ b/vike/node/runtime/renderPage/getEarlyHints.ts
@@ -1,9 +1,9 @@
 export { getEarlyHints }
 export type { EarlyHint }
 
-import { inferEarlyHintLink } from '../html/injectAssets/inferHtmlTags.js'
-import { assert } from '../utils.js'
-import type { PageAsset } from './getPageAssets.js'
+import { inferEarlyHintLink } from '../html/injectAssets/inferHtmlTags'
+import { assert } from '../utils'
+import type { PageAsset } from './getPageAssets'
 
 type EarlyHint = PageAsset & {
   earlyHintLink: string
diff --git a/vike/node/runtime/renderPage/getHttpResponseBody.ts b/vike/node/runtime/renderPage/getHttpResponseBody.ts
index 86fcb413c7..67122e16a9 100644
--- a/vike/node/runtime/renderPage/getHttpResponseBody.ts
+++ b/vike/node/runtime/renderPage/getHttpResponseBody.ts
@@ -22,10 +22,10 @@ import {
   getStreamReadableWeb,
   pipeToStreamWritableWeb,
   pipeToStreamWritableNode
-} from '../html/stream.js'
-import { assert, assertUsage, assertWarning } from '../utils.js'
-import { getHtmlString, type HtmlRender } from '../html/renderHtml.js'
-import type { RenderHook } from './executeOnRenderHtmlHook.js'
+} from '../html/stream'
+import { assert, assertUsage, assertWarning } from '../utils'
+import { getHtmlString, type HtmlRender } from '../html/renderHtml'
+import type { RenderHook } from './executeOnRenderHtmlHook'
 import pc from '@brillout/picocolors'
 
 const streamDocs = 'See https://vike.dev/streaming for more information.'
diff --git a/vike/node/runtime/renderPage/getPageAssets.ts b/vike/node/runtime/renderPage/getPageAssets.ts
index a3523c5585..71129ab0aa 100644
--- a/vike/node/runtime/renderPage/getPageAssets.ts
+++ b/vike/node/runtime/renderPage/getPageAssets.ts
@@ -4,16 +4,16 @@ export type { PageAsset }
 export type { GetPageAssets }
 export type { PageContextGetPageAssets }
 
-import { assert, prependBase, toPosixPath, unique, getGlobalObject } from '../utils.js'
-import { retrieveAssetsDev } from './getPageAssets/retrieveAssetsDev.js'
-import { retrieveAssetsProd } from './getPageAssets/retrieveAssetsProd.js'
-import { inferMediaType, type MediaType } from './inferMediaType.js'
-import { getManifestEntry } from './getPageAssets/getManifestEntry.js'
-import type { ClientDependency } from '../../../shared/getPageFiles/analyzePageClientSide/ClientDependency.js'
-import { sortPageAssetsForEarlyHintsHeader } from './getPageAssets/sortPageAssetsForEarlyHintsHeader.js'
-import { getGlobalContext } from '../globalContext.js'
-import type { ViteManifest } from '../../shared/ViteManifest.js'
-import type { ResolveClientEntriesDev } from '../../plugin/resolveClientEntriesDev.js'
+import { assert, prependBase, toPosixPath, unique, getGlobalObject } from '../utils'
+import { retrieveAssetsDev } from './getPageAssets/retrieveAssetsDev'
+import { retrieveAssetsProd } from './getPageAssets/retrieveAssetsProd'
+import { inferMediaType, type MediaType } from './inferMediaType'
+import { getManifestEntry } from './getPageAssets/getManifestEntry'
+import type { ClientDependency } from '../../../shared/getPageFiles/analyzePageClientSide/ClientDependency'
+import { sortPageAssetsForEarlyHintsHeader } from './getPageAssets/sortPageAssetsForEarlyHintsHeader'
+import { getGlobalContext } from '../globalContext'
+import type { ViteManifest } from '../../shared/ViteManifest'
+import type { ResolveClientEntriesDev } from '../../plugin/resolveClientEntriesDev'
 
 const globalObject = getGlobalObject('getPageAssets.ts', {
   resolveClientEntriesDev: null as null | ResolveClientEntriesDev
diff --git a/vike/node/runtime/renderPage/getPageAssets/getManifestEntry.ts b/vike/node/runtime/renderPage/getPageAssets/getManifestEntry.ts
index 1515c7c4bd..7de2a1122a 100644
--- a/vike/node/runtime/renderPage/getPageAssets/getManifestEntry.ts
+++ b/vike/node/runtime/renderPage/getPageAssets/getManifestEntry.ts
@@ -1,9 +1,9 @@
 export { getManifestEntry }
 
-import type { ViteManifest, ViteManifestEntry } from '../../../shared/ViteManifest.js'
-import { assert, slice, assertIsNpmPackageImport } from '../../utils.js'
-import { isVirtualFileIdPageConfigValuesAll } from '../../../shared/virtual-files/virtualFilePageConfigValuesAll.js'
-import { prependEntriesDir } from '../../../shared/prependEntriesDir.js'
+import type { ViteManifest, ViteManifestEntry } from '../../../shared/ViteManifest'
+import { assert, slice, assertIsNpmPackageImport } from '../../utils'
+import { isVirtualFileIdPageConfigValuesAll } from '../../../shared/virtual-files/virtualFilePageConfigValuesAll'
+import { prependEntriesDir } from '../../../shared/prependEntriesDir'
 
 function getManifestEntry(
   id: string,
diff --git a/vike/node/runtime/renderPage/getPageAssets/retrieveAssetsDev.ts b/vike/node/runtime/renderPage/getPageAssets/retrieveAssetsDev.ts
index 920ac495ff..ad921f198c 100644
--- a/vike/node/runtime/renderPage/getPageAssets/retrieveAssetsDev.ts
+++ b/vike/node/runtime/renderPage/getPageAssets/retrieveAssetsDev.ts
@@ -1,8 +1,8 @@
 export { retrieveAssetsDev }
 
-import { assert, styleFileRE } from '../../utils.js'
+import { assert, styleFileRE } from '../../utils'
 import type { ModuleNode, ViteDevServer } from 'vite'
-import type { ClientDependency } from '../../../../shared/getPageFiles/analyzePageClientSide/ClientDependency.js'
+import type { ClientDependency } from '../../../../shared/getPageFiles/analyzePageClientSide/ClientDependency'
 
 async function retrieveAssetsDev(clientDependencies: ClientDependency[], viteDevServer: ViteDevServer) {
   const visitedModules = new Set<string>()
diff --git a/vike/node/runtime/renderPage/getPageAssets/retrieveAssetsProd.ts b/vike/node/runtime/renderPage/getPageAssets/retrieveAssetsProd.ts
index 77aa6e1f1d..d891146595 100644
--- a/vike/node/runtime/renderPage/getPageAssets/retrieveAssetsProd.ts
+++ b/vike/node/runtime/renderPage/getPageAssets/retrieveAssetsProd.ts
@@ -1,10 +1,10 @@
 export { retrieveAssetsProd }
 
-import { assert, isNpmPackageImport } from '../../utils.js'
-import type { ViteManifest } from '../../../shared/ViteManifest.js'
-import { getManifestEntry } from './getManifestEntry.js'
-import { extractAssetsAddQuery } from '../../../shared/extractAssetsQuery.js'
-import type { ClientDependency } from '../../../../shared/getPageFiles/analyzePageClientSide/ClientDependency.js'
+import { assert, isNpmPackageImport } from '../../utils'
+import type { ViteManifest } from '../../../shared/ViteManifest'
+import { getManifestEntry } from './getManifestEntry'
+import { extractAssetsAddQuery } from '../../../shared/extractAssetsQuery'
+import type { ClientDependency } from '../../../../shared/getPageFiles/analyzePageClientSide/ClientDependency'
 
 function retrieveAssetsProd(
   clientDependencies: ClientDependency[],
diff --git a/vike/node/runtime/renderPage/getPageAssets/sortPageAssetsForEarlyHintsHeader.ts b/vike/node/runtime/renderPage/getPageAssets/sortPageAssetsForEarlyHintsHeader.ts
index a3b92bdefe..b76335d8cf 100644
--- a/vike/node/runtime/renderPage/getPageAssets/sortPageAssetsForEarlyHintsHeader.ts
+++ b/vike/node/runtime/renderPage/getPageAssets/sortPageAssetsForEarlyHintsHeader.ts
@@ -1,8 +1,8 @@
 export { sortPageAssetsForEarlyHintsHeader }
 
-import { getGlobalContext } from '../../globalContext.js'
-import { higherFirst } from '../../utils.js'
-import type { PageAsset } from '../getPageAssets.js'
+import { getGlobalContext } from '../../globalContext'
+import { higherFirst } from '../../utils'
+import type { PageAsset } from '../getPageAssets'
 
 function sortPageAssetsForEarlyHintsHeader(pageAssets: PageAsset[]) {
   const globalContext = getGlobalContext()
diff --git a/vike/node/runtime/renderPage/handleErrorWithoutErrorPage.ts b/vike/node/runtime/renderPage/handleErrorWithoutErrorPage.ts
index 54bb937e2a..667bfc4695 100644
--- a/vike/node/runtime/renderPage/handleErrorWithoutErrorPage.ts
+++ b/vike/node/runtime/renderPage/handleErrorWithoutErrorPage.ts
@@ -1,14 +1,14 @@
 export { handleErrorWithoutErrorPage }
 
 import { stringify } from '@brillout/json-serializer/stringify'
-import { getGlobalContext } from '../globalContext.js'
-import { assert, assertWarning, objectAssign } from '../utils.js'
-import { createHttpResponsePage, createHttpResponseError } from './createHttpResponse.js'
+import { getGlobalContext } from '../globalContext'
+import { assert, assertWarning, objectAssign } from '../utils'
+import { createHttpResponsePage, createHttpResponseError } from './createHttpResponse'
 import pc from '@brillout/picocolors'
-import type { GetPageAssets } from './getPageAssets.js'
-import type { PageContextAfterRender } from './renderPageAlreadyRouted.js'
-import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig.js'
-import type { PageFile } from '../../../shared/getPageFiles.js'
+import type { GetPageAssets } from './getPageAssets'
+import type { PageContextAfterRender } from './renderPageAlreadyRouted'
+import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig'
+import type { PageFile } from '../../../shared/getPageFiles'
 
 // When the user hasn't defined _error.page.js
 async function handleErrorWithoutErrorPage<
diff --git a/vike/node/runtime/renderPage/handlePageContextRequestUrl.ts b/vike/node/runtime/renderPage/handlePageContextRequestUrl.ts
index 1a96f6c381..5c29becb7e 100644
--- a/vike/node/runtime/renderPage/handlePageContextRequestUrl.ts
+++ b/vike/node/runtime/renderPage/handlePageContextRequestUrl.ts
@@ -1,7 +1,7 @@
 export { handlePageContextRequestUrl }
 
-import { pageContextJsonFileExtension, doNotCreateExtraDirectory } from '../../../shared/getPageContextRequestUrl.js'
-import { baseServer, parseUrl, assert, slice } from '../utils.js'
+import { pageContextJsonFileExtension, doNotCreateExtraDirectory } from '../../../shared/getPageContextRequestUrl'
+import { baseServer, parseUrl, assert, slice } from '../utils'
 
 // See shared/getPageContextRequestUrl.ts
 function handlePageContextRequestUrl(url: string): {
diff --git a/vike/node/runtime/renderPage/inferMediaType.ts b/vike/node/runtime/renderPage/inferMediaType.ts
index f745cf8d76..26510e2b07 100644
--- a/vike/node/runtime/renderPage/inferMediaType.ts
+++ b/vike/node/runtime/renderPage/inferMediaType.ts
@@ -1,7 +1,7 @@
 export { inferMediaType }
 export type { MediaType }
 
-import { styleFileRE, isScriptFile } from '../utils.js'
+import { styleFileRE, isScriptFile } from '../utils'
 
 type MediaType = null | {
   // List of `as` values: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-as
diff --git a/vike/node/runtime/renderPage/isConfigInvalid.ts b/vike/node/runtime/renderPage/isConfigInvalid.ts
index 34c1f9731b..1513af6f9d 100644
--- a/vike/node/runtime/renderPage/isConfigInvalid.ts
+++ b/vike/node/runtime/renderPage/isConfigInvalid.ts
@@ -1,7 +1,7 @@
 export { isConfigInvalid }
 export { isConfigInvalid_set }
 
-import { assert } from '../utils.js'
+import { assert } from '../utils'
 
 let isConfigInvalid: false | { err: unknown }
 
diff --git a/vike/node/runtime/renderPage/isNewError.ts b/vike/node/runtime/renderPage/isNewError.ts
index 24dac90bc6..33bbcc28d2 100644
--- a/vike/node/runtime/renderPage/isNewError.ts
+++ b/vike/node/runtime/renderPage/isNewError.ts
@@ -1,7 +1,7 @@
 export { isNewError }
 export { setAlreadyLogged }
 
-import { getGlobalObject, isObject, isSameErrorMessage, warnIfErrorIsNotObject } from '../utils.js'
+import { getGlobalObject, isObject, isSameErrorMessage, warnIfErrorIsNotObject } from '../utils'
 
 const globalObject = getGlobalObject('runtime/renderPage/isNewError.ts', {
   wasAlreadyLogged: new WeakSet<object>()
diff --git a/vike/node/runtime/renderPage/loadUserFilesServerSide.ts b/vike/node/runtime/renderPage/loadUserFilesServerSide.ts
index e3bfec0dcb..f04ac369d9 100644
--- a/vike/node/runtime/renderPage/loadUserFilesServerSide.ts
+++ b/vike/node/runtime/renderPage/loadUserFilesServerSide.ts
@@ -2,8 +2,8 @@ export { loadUserFilesServerSide }
 export type { PageFiles }
 export type { PageContext_loadUserFilesServerSide }
 
-import { type PageFile, getPageFilesServerSide, getPageContextExports } from '../../../shared/getPageFiles.js'
-import { analyzePageClientSideInit } from '../../../shared/getPageFiles/analyzePageClientSide.js'
+import { type PageFile, getPageFilesServerSide, getPageContextExports } from '../../../shared/getPageFiles'
+import { analyzePageClientSideInit } from '../../../shared/getPageFiles/analyzePageClientSide'
 import {
   assert,
   assertUsage,
@@ -13,15 +13,15 @@ import {
   objectAssign,
   PromiseType,
   isArray
-} from '../utils.js'
-import { getPageAssets, PageContextGetPageAssets, type PageAsset } from './getPageAssets.js'
-import { debugPageFiles, type PageContextDebugRouteMatches } from './debugPageFiles.js'
-import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig.js'
-import { findPageConfig } from '../../../shared/page-configs/findPageConfig.js'
-import { analyzePage } from './analyzePage.js'
-import { getGlobalContext } from '../globalContext.js'
-import type { MediaType } from './inferMediaType.js'
-import { loadConfigValues } from '../../../shared/page-configs/loadConfigValues.js'
+} from '../utils'
+import { getPageAssets, PageContextGetPageAssets, type PageAsset } from './getPageAssets'
+import { debugPageFiles, type PageContextDebugRouteMatches } from './debugPageFiles'
+import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig'
+import { findPageConfig } from '../../../shared/page-configs/findPageConfig'
+import { analyzePage } from './analyzePage'
+import { getGlobalContext } from '../globalContext'
+import type { MediaType } from './inferMediaType'
+import { loadConfigValues } from '../../../shared/page-configs/loadConfigValues'
 
 type PageContext_loadUserFilesServerSide = PageContextGetPageAssets &
   PageContextDebugRouteMatches & {
diff --git a/vike/node/runtime/renderPage/log404/index.spec.ts b/vike/node/runtime/renderPage/log404/index.spec.ts
index 41ea36b268..dce884d671 100644
--- a/vike/node/runtime/renderPage/log404/index.spec.ts
+++ b/vike/node/runtime/renderPage/log404/index.spec.ts
@@ -1,7 +1,7 @@
 import { expect, describe, it, assert } from 'vitest'
-import { getRoutesInfo } from '../log404/index.js'
-import { stripAnsi } from '../../utils.js'
-import type { PageRoutes } from '../../../../shared/route/index.js'
+import { getRoutesInfo } from '../log404/index'
+import { stripAnsi } from '../../utils'
+import type { PageRoutes } from '../../../../shared/route/index'
 
 process.stdout.columns = 134
 
diff --git a/vike/node/runtime/renderPage/log404/index.ts b/vike/node/runtime/renderPage/log404/index.ts
index 7ef68107d7..61381822e4 100644
--- a/vike/node/runtime/renderPage/log404/index.ts
+++ b/vike/node/runtime/renderPage/log404/index.ts
@@ -3,9 +3,9 @@ export { log404 }
 // Exported for ./index.spec.ts
 export { getRoutesInfo }
 
-import type { PageRoutes } from '../../../../shared/route/index.js'
-import { noRouteMatch } from '../../../../shared/route/noRouteMatch.js'
-import { getGlobalContext } from '../../globalContext.js'
+import type { PageRoutes } from '../../../../shared/route/index'
+import { noRouteMatch } from '../../../../shared/route/noRouteMatch'
+import { getGlobalContext } from '../../globalContext'
 import {
   assert,
   assertUsage,
@@ -14,7 +14,7 @@ import {
   stripAnsi,
   getTerminalWidth,
   truncateString
-} from '../../utils.js'
+} from '../../utils'
 import pc from '@brillout/picocolors'
 
 async function log404(pageContext: {
diff --git a/vike/node/runtime/renderPage/logErrorHint.ts b/vike/node/runtime/renderPage/logErrorHint.ts
index d38870610d..961fe64043 100644
--- a/vike/node/runtime/renderPage/logErrorHint.ts
+++ b/vike/node/runtime/renderPage/logErrorHint.ts
@@ -2,7 +2,7 @@ export { logErrorHint }
 // For ./logErrorHint/getErrorHint.spec.ts
 export { getErrorHint }
 
-import { assert, formatHintLog, isObject } from '../utils.js'
+import { assert, formatHintLog, isObject } from '../utils'
 import pc from '@brillout/picocolors'
 
 const hintDefault = 'The error could be a CJS/ESM issue, see https://vike.dev/broken-npm-package'
diff --git a/vike/node/runtime/renderPage/loggerProd.ts b/vike/node/runtime/renderPage/loggerProd.ts
index 98cdcbdd04..4c645a32e8 100644
--- a/vike/node/runtime/renderPage/loggerProd.ts
+++ b/vike/node/runtime/renderPage/loggerProd.ts
@@ -4,11 +4,11 @@
 export { logErrorProd }
 export { onRuntimeError }
 
-import { isAbortError } from '../../../shared/route/abort.js'
-import { setAlreadyLogged } from './isNewError.js'
-import { isObject, warnIfErrorIsNotObject } from '../utils.js'
+import { isAbortError } from '../../../shared/route/abort'
+import { setAlreadyLogged } from './isNewError'
+import { isObject, warnIfErrorIsNotObject } from '../utils'
 import pc from '@brillout/picocolors'
-import { logErrorHint } from './logErrorHint.js'
+import { logErrorHint } from './logErrorHint'
 
 function logErrorProd(err: unknown, _httpRquestId: null | number): void {
   warnIfErrorIsNotObject(err)
diff --git a/vike/node/runtime/renderPage/loggerRuntime.ts b/vike/node/runtime/renderPage/loggerRuntime.ts
index ab71b88b29..7b0705c08a 100644
--- a/vike/node/runtime/renderPage/loggerRuntime.ts
+++ b/vike/node/runtime/renderPage/loggerRuntime.ts
@@ -4,8 +4,8 @@ export let logRuntimeError: LogError
 export let logRuntimeInfo: null | LogInfo = null // logInfo is null in production
 export { overwriteRuntimeProductionLogger }
 
-import { logErrorProd } from './loggerProd.js'
-import type { LogError, LogInfo } from '../../plugin/shared/loggerNotProd.js'
+import { logErrorProd } from './loggerProd'
+import type { LogError, LogInfo } from '../../plugin/shared/loggerNotProd'
 
 // Set production logger (which is overwritten by loggerNotProd.ts in non-production environments such as development and during pre-rendering)
 logRuntimeError =
diff --git a/vike/node/runtime/renderPage/preparePageContextForUserConsumptionServerSide.ts b/vike/node/runtime/renderPage/preparePageContextForUserConsumptionServerSide.ts
index 1837c106fb..91917254c5 100644
--- a/vike/node/runtime/renderPage/preparePageContextForUserConsumptionServerSide.ts
+++ b/vike/node/runtime/renderPage/preparePageContextForUserConsumptionServerSide.ts
@@ -1,12 +1,12 @@
 export { preparePageContextForUserConsumptionServerSide }
 export type { PageContextForUserConsumptionServerSide }
 
-import { assert, isPlainObject } from '../utils.js'
-import { assertPageContextUrl, PageContextUrlInternal } from '../../../shared/getPageContextUrlComputed.js'
-import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig.js'
-import type { PageContextExports } from '../../../shared/getPageFiles/getExports.js'
-import { PageContextBuiltInServerInternal } from '../../../shared/types.js'
-import { preparePageContextForUserConsumption } from '../../../shared/preparePageContextForUserConsumption.js'
+import { assert, isPlainObject } from '../utils'
+import { assertPageContextUrl, PageContextUrlInternal } from '../../../shared/getPageContextUrlComputed'
+import type { PageConfigRuntime } from '../../../shared/page-configs/PageConfig'
+import type { PageContextExports } from '../../../shared/getPageFiles/getExports'
+import { PageContextBuiltInServerInternal } from '../../../shared/types'
+import { preparePageContextForUserConsumption } from '../../../shared/preparePageContextForUserConsumption'
 
 type PageContextForUserConsumptionServerSide = PageContextBuiltInServerInternal &
   PageContextExports & {
diff --git a/vike/node/runtime/renderPage/renderPageAlreadyRouted.ts b/vike/node/runtime/renderPage/renderPageAlreadyRouted.ts
index 17ffc21d32..d55c2edcc6 100644
--- a/vike/node/runtime/renderPage/renderPageAlreadyRouted.ts
+++ b/vike/node/runtime/renderPage/renderPageAlreadyRouted.ts
@@ -7,31 +7,31 @@ export type { RenderContext }
 export type { PageContextAfterRender }
 export type { PageContextInitEnhanced }
 
-import { getErrorPageId } from '../../../shared/error-page.js'
-import { getHtmlString } from '../html/renderHtml.js'
-import { type PageFile, getPageFilesAll } from '../../../shared/getPageFiles.js'
-import { assert, assertUsage, assertWarning, hasProp, normalizeHeaders, objectAssign } from '../utils.js'
-import { serializePageContextClientSide } from '../html/serializePageContextClientSide.js'
-import { getPageContextUrlComputed, type PageContextUrlInternal } from '../../../shared/getPageContextUrlComputed.js'
-import { getGlobalContext } from '../globalContext.js'
-import { createHttpResponsePage, createHttpResponsePageContextJson, HttpResponse } from './createHttpResponse.js'
+import { getErrorPageId } from '../../../shared/error-page'
+import { getHtmlString } from '../html/renderHtml'
+import { type PageFile, getPageFilesAll } from '../../../shared/getPageFiles'
+import { assert, assertUsage, assertWarning, hasProp, normalizeHeaders, objectAssign } from '../utils'
+import { serializePageContextClientSide } from '../html/serializePageContextClientSide'
+import { getPageContextUrlComputed, type PageContextUrlInternal } from '../../../shared/getPageContextUrlComputed'
+import { getGlobalContext } from '../globalContext'
+import { createHttpResponsePage, createHttpResponsePageContextJson, HttpResponse } from './createHttpResponse'
 import {
   loadUserFilesServerSide,
   PageContext_loadUserFilesServerSide,
   type PageFiles
-} from './loadUserFilesServerSide.js'
-import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../../../shared/page-configs/PageConfig.js'
-import { executeOnRenderHtmlHook } from './executeOnRenderHtmlHook.js'
-import { executeOnBeforeRenderAndDataHooks } from './executeOnBeforeRenderAndDataHooks.js'
-import { logRuntimeError } from './loggerRuntime.js'
-import { isNewError } from './isNewError.js'
-import { preparePageContextForUserConsumptionServerSide } from './preparePageContextForUserConsumptionServerSide.js'
-import { executeGuardHook } from '../../../shared/route/executeGuardHook.js'
-import { loadPageRoutes, type PageRoutes } from '../../../shared/route/loadPageRoutes.js'
+} from './loadUserFilesServerSide'
+import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../../../shared/page-configs/PageConfig'
+import { executeOnRenderHtmlHook } from './executeOnRenderHtmlHook'
+import { executeOnBeforeRenderAndDataHooks } from './executeOnBeforeRenderAndDataHooks'
+import { logRuntimeError } from './loggerRuntime'
+import { isNewError } from './isNewError'
+import { preparePageContextForUserConsumptionServerSide } from './preparePageContextForUserConsumptionServerSide'
+import { executeGuardHook } from '../../../shared/route/executeGuardHook'
+import { loadPageRoutes, type PageRoutes } from '../../../shared/route/loadPageRoutes'
 import pc from '@brillout/picocolors'
-import type { Hook } from '../../../shared/hooks/getHook.js'
-import { isServerSideError } from '../../../shared/misc/isServerSideError.js'
-import { assertV1Design } from '../../shared/assertV1Design.js'
+import type { Hook } from '../../../shared/hooks/getHook'
+import { isServerSideError } from '../../../shared/misc/isServerSideError'
+import { assertV1Design } from '../../shared/assertV1Design'
 
 type PageContextAfterRender = { httpResponse: HttpResponse; errorWhileRendering: null | Error }
 
diff --git a/vike/node/runtime/renderPage/resolveRedirects.spec.ts b/vike/node/runtime/renderPage/resolveRedirects.spec.ts
index 9b89ea7065..03eb603a76 100644
--- a/vike/node/runtime/renderPage/resolveRedirects.spec.ts
+++ b/vike/node/runtime/renderPage/resolveRedirects.spec.ts
@@ -1,5 +1,5 @@
-import { resolveRouteStringRedirect } from './resolveRedirects.js'
-import { stripAnsi } from '../../../utils/stripAnsi.js'
+import { resolveRouteStringRedirect } from './resolveRedirects'
+import { stripAnsi } from '../../../utils/stripAnsi'
 import { expect, describe, it } from 'vitest'
 
 describe('resolveRouteStringRedirect', () => {
diff --git a/vike/node/runtime/renderPage/resolveRedirects.ts b/vike/node/runtime/renderPage/resolveRedirects.ts
index f7b1673784..d72e46a67d 100644
--- a/vike/node/runtime/renderPage/resolveRedirects.ts
+++ b/vike/node/runtime/renderPage/resolveRedirects.ts
@@ -3,10 +3,10 @@ export { resolveRedirects }
 // For ./resolveRedirects.spec.ts
 export { resolveRouteStringRedirect }
 
-import { assertIsNotBrowser } from '../../../utils/assertIsNotBrowser.js'
-import { assert, assertUsage, assertUsageUrlRedirectTarget, isUrlRedirectTarget } from '../../../shared/utils.js'
-import { resolveUrlPathname } from '../../../shared/route/resolveUrlPathname.js'
-import { assertRouteString, resolveRouteString } from '../../../shared/route/resolveRouteString.js'
+import { assertIsNotBrowser } from '../../../utils/assertIsNotBrowser'
+import { assert, assertUsage, assertUsageUrlRedirectTarget, isUrlRedirectTarget } from '../../../shared/utils'
+import { resolveUrlPathname } from '../../../shared/route/resolveUrlPathname'
+import { assertRouteString, resolveRouteString } from '../../../shared/route/resolveRouteString'
 import pc from '@brillout/picocolors'
 assertIsNotBrowser() // Don't bloat the client
 
diff --git a/vike/node/runtime/utils.ts b/vike/node/runtime/utils.ts
index d90f92c4f4..edcd4f4f11 100644
--- a/vike/node/runtime/utils.ts
+++ b/vike/node/runtime/utils.ts
@@ -1,64 +1,64 @@
-import '../../utils/trackLogs.js'
+import '../../utils/trackLogs'
 
 // We assume all runtime entries will load this utils.ts file
-import { onLoad } from './onLoad.js'
+import { onLoad } from './onLoad'
 onLoad()
 
-export * from '../../utils/assert.js'
-export * from '../../utils/cast.js'
-export * from '../../utils/checkType.js'
-export * from '../../utils/isCallable.js'
-export * from '../../utils/isBrowser.js'
-export * from '../../utils/isPlainObject.js'
-export * from '../../utils/isPromise.js'
-export * from '../../utils/hasProp.js'
-export * from '../../utils/parseUrl.js'
-export * from '../../utils/parseUrl-extras.js'
-export * from '../../utils/slice.js'
-export * from '../../utils/sorter.js'
-export * from '../../utils/projectInfo.js'
-export * from '../../utils/isArray.js'
-export * from '../../utils/isObject.js'
-export * from '../../utils/objectAssign.js'
-export * from '../../utils/PromiseType.js'
-export * from '../../utils/compareString.js'
-export * from '../../utils/isObjectWithKeys.js'
-export * from '../../utils/stringifyStringArray.js'
-export * from '../../utils/unique.js'
-export * from '../../utils/filesystemPathHandling.js'
-export * from '../../utils/getOutDirs.js'
-export * from '../../utils/capitalizeFirstLetter.js'
-export * from '../../utils/debugGlob.js'
-export * from '../../utils/isSameErrorMessage.js'
-export * from '../../utils/styleFileRE.js'
-export * from '../../utils/isPropertyGetter.js'
-export * from '../../utils/debug.js'
-export * from '../../utils/urlToFile.js'
-export * from '../../utils/getGlobalObject.js'
-export * from '../../utils/freezePartial.js'
-export * from '../../utils/isNpmPackage.js'
-export * from '../../utils/isNotNullish.js'
-export * from '../../utils/isScriptFile.js'
-export * from '../../utils/removeFileExtention.js'
-export * from '../../utils/objectKeys.js'
-export * from '../../utils/objectEntries.js'
-export * from '../../utils/objectFromEntries.js'
-export * from '../../utils/getFileExtension.js'
-export * from '../../utils/assertIsNotProductionRuntime.js'
-export * from '../../utils/virtual-files.js'
-export * from '../../utils/path-shim.js'
-export * from '../../utils/assertNodeEnv.js'
-export * from '../../utils/isHtml.js'
-export * from '../../utils/warnIfErrorIsNotObject.js'
-export * from '../../utils/stripAnsi.js'
-export * from '../../utils/getTerminWidth.js'
-export * from '../../utils/truncateString.js'
-export * from '../../utils/formatHintLog.js'
-export * from '../../utils/joinEnglish.js'
-export * from '../../utils/isArrayOfStrings.js'
-export * from '../../utils/escapeHtml.js'
-export * from '../../utils/normalizeHeaders.js'
-export * from '../../utils/isVikeReactApp.js'
-export * from '../../utils/getPropAccessNotation.js'
-export * from '../../utils/PROJECT_VERSION.js'
-export * from '../../utils/genPromise.js'
+export * from '../../utils/assert'
+export * from '../../utils/cast'
+export * from '../../utils/checkType'
+export * from '../../utils/isCallable'
+export * from '../../utils/isBrowser'
+export * from '../../utils/isPlainObject'
+export * from '../../utils/isPromise'
+export * from '../../utils/hasProp'
+export * from '../../utils/parseUrl'
+export * from '../../utils/parseUrl-extras'
+export * from '../../utils/slice'
+export * from '../../utils/sorter'
+export * from '../../utils/projectInfo'
+export * from '../../utils/isArray'
+export * from '../../utils/isObject'
+export * from '../../utils/objectAssign'
+export * from '../../utils/PromiseType'
+export * from '../../utils/compareString'
+export * from '../../utils/isObjectWithKeys'
+export * from '../../utils/stringifyStringArray'
+export * from '../../utils/unique'
+export * from '../../utils/filesystemPathHandling'
+export * from '../../utils/getOutDirs'
+export * from '../../utils/capitalizeFirstLetter'
+export * from '../../utils/debugGlob'
+export * from '../../utils/isSameErrorMessage'
+export * from '../../utils/styleFileRE'
+export * from '../../utils/isPropertyGetter'
+export * from '../../utils/debug'
+export * from '../../utils/urlToFile'
+export * from '../../utils/getGlobalObject'
+export * from '../../utils/freezePartial'
+export * from '../../utils/isNpmPackage'
+export * from '../../utils/isNotNullish'
+export * from '../../utils/isScriptFile'
+export * from '../../utils/removeFileExtention'
+export * from '../../utils/objectKeys'
+export * from '../../utils/objectEntries'
+export * from '../../utils/objectFromEntries'
+export * from '../../utils/getFileExtension'
+export * from '../../utils/assertIsNotProductionRuntime'
+export * from '../../utils/virtual-files'
+export * from '../../utils/path-shim'
+export * from '../../utils/assertNodeEnv'
+export * from '../../utils/isHtml'
+export * from '../../utils/warnIfErrorIsNotObject'
+export * from '../../utils/stripAnsi'
+export * from '../../utils/getTerminWidth'
+export * from '../../utils/truncateString'
+export * from '../../utils/formatHintLog'
+export * from '../../utils/joinEnglish'
+export * from '../../utils/isArrayOfStrings'
+export * from '../../utils/escapeHtml'
+export * from '../../utils/normalizeHeaders'
+export * from '../../utils/isVikeReactApp'
+export * from '../../utils/getPropAccessNotation'
+export * from '../../utils/PROJECT_VERSION'
+export * from '../../utils/genPromise'
diff --git a/vike/node/shared/assertPluginManifest.ts b/vike/node/shared/assertPluginManifest.ts
index 7805debe48..9523623582 100644
--- a/vike/node/shared/assertPluginManifest.ts
+++ b/vike/node/shared/assertPluginManifest.ts
@@ -1,8 +1,8 @@
 export { assertPluginManifest }
 export type { PluginManifest }
 
-import { assertRuntimeManifest } from './assertRuntimeManifest.js'
-import { assert, assertUsage, isPlainObject, projectInfo, checkType, hasProp } from './utils.js'
+import { assertRuntimeManifest } from './assertRuntimeManifest'
+import { assert, assertUsage, isPlainObject, projectInfo, checkType, hasProp } from './utils'
 
 type PluginManifest = {
   version: string
diff --git a/vike/node/shared/assertRuntimeManifest.ts b/vike/node/shared/assertRuntimeManifest.ts
index 191dc6caea..b08c3350b6 100644
--- a/vike/node/shared/assertRuntimeManifest.ts
+++ b/vike/node/shared/assertRuntimeManifest.ts
@@ -1,7 +1,7 @@
 export { assertRuntimeManifest }
 export type { RuntimeManifest }
 
-import { assert, castType, checkType, hasProp, isBaseAssets, isBaseServer, isObject } from './utils.js'
+import { assert, castType, checkType, hasProp, isBaseAssets, isBaseServer, isObject } from './utils'
 
 type RuntimeManifest = {
   baseServer: string
diff --git a/vike/node/shared/assertV1Design.ts b/vike/node/shared/assertV1Design.ts
index b027664e3c..829d374672 100644
--- a/vike/node/shared/assertV1Design.ts
+++ b/vike/node/shared/assertV1Design.ts
@@ -2,9 +2,9 @@ export { assertV1Design }
 
 // TODO/next-major-release: remove
 
-import { PageFile } from '../../shared/getPageFiles.js'
-import type { PageConfigBuildTime } from '../../shared/page-configs/PageConfig.js'
-import { assert, assertUsage, assertWarning, isNotNullish, unique } from './utils.js'
+import { PageFile } from '../../shared/getPageFiles'
+import type { PageConfigBuildTime } from '../../shared/page-configs/PageConfig'
+import { assert, assertUsage, assertWarning, isNotNullish, unique } from './utils'
 
 function assertV1Design(pageConfigs: PageConfigBuildTime[] | boolean, pageFilesAll: PageFile[] | boolean): void {
   const isOldDesign = pageFilesAll === true || (pageFilesAll !== false && pageFilesAll.length > 0)
diff --git a/vike/node/shared/extractAssetsQuery.ts b/vike/node/shared/extractAssetsQuery.ts
index 5cade9a5dc..30d7ca3266 100644
--- a/vike/node/shared/extractAssetsQuery.ts
+++ b/vike/node/shared/extractAssetsQuery.ts
@@ -2,7 +2,7 @@ export { extractAssetsAddQuery }
 export { extractAssetsRemoveQuery }
 
 // We import from node/utils.ts insead of node/plugin/utils.ts because this file is loaded by the server runtime
-import { assert, getFileExtension } from './utils.js'
+import { assert, getFileExtension } from './utils'
 
 const query = 'extractAssets'
 
diff --git a/vike/node/shared/getConfigVike.ts b/vike/node/shared/getConfigVike.ts
index e8e79e2b5d..b421e65406 100644
--- a/vike/node/shared/getConfigVike.ts
+++ b/vike/node/shared/getConfigVike.ts
@@ -1,8 +1,8 @@
 export { getConfigVike }
 
 import { ResolvedConfig } from 'vite'
-import type { ConfigVikeResolved } from '../../shared/ConfigVike.js'
-import { assert } from './utils.js'
+import type { ConfigVikeResolved } from '../../shared/ConfigVike'
+import { assert } from './utils'
 
 async function getConfigVike(config: ResolvedConfig): Promise<ConfigVikeResolved> {
   const { configVikePromise } = config as any
diff --git a/vike/node/shared/isErrorDebug.ts b/vike/node/shared/isErrorDebug.ts
index ada8921959..c49341d60c 100644
--- a/vike/node/shared/isErrorDebug.ts
+++ b/vike/node/shared/isErrorDebug.ts
@@ -1,6 +1,6 @@
 export { isErrorDebug }
 
-import { isDebugActivated } from './utils.js'
+import { isDebugActivated } from './utils'
 
 function isErrorDebug(): boolean {
   return isDebugActivated('vike:error')
diff --git a/vike/node/shared/prependEntriesDir.ts b/vike/node/shared/prependEntriesDir.ts
index 1069891685..fab7813b06 100644
--- a/vike/node/shared/prependEntriesDir.ts
+++ b/vike/node/shared/prependEntriesDir.ts
@@ -1,6 +1,6 @@
 export { prependEntriesDir }
 
-import { assert } from './utils.js'
+import { assert } from './utils'
 
 function prependEntriesDir(entryName: string): string {
   if (entryName.startsWith('/')) {
diff --git a/vike/node/shared/utils.ts b/vike/node/shared/utils.ts
index c56a251298..c5b1a79bad 100644
--- a/vike/node/shared/utils.ts
+++ b/vike/node/shared/utils.ts
@@ -1,20 +1,20 @@
-import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser.js'
+import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser'
 assertIsNotBrowser()
 
-export * from '../../utils/assert.js'
-export * from '../../utils/getFileExtension.js'
-export * from '../../utils/isPlainObject.js'
-export * from '../../utils/projectInfo.js'
-export * from '../../utils/checkType.js'
-export * from '../../utils/hasProp.js'
-export * from '../../utils/objectAssign.js'
-export * from '../../utils/checkType.js'
-export * from '../../utils/hasProp.js'
-export * from '../../utils/parseUrl.js'
-export * from '../../utils/parseUrl-extras.js'
-export * from '../../utils/isObject.js'
-export * from '../../utils/virtual-files.js'
-export * from '../../utils/assertIsNotBrowser.js'
-export * from '../../utils/isNotNullish.js'
-export * from '../../utils/unique.js'
-export * from '../../utils/debug.js'
+export * from '../../utils/assert'
+export * from '../../utils/getFileExtension'
+export * from '../../utils/isPlainObject'
+export * from '../../utils/projectInfo'
+export * from '../../utils/checkType'
+export * from '../../utils/hasProp'
+export * from '../../utils/objectAssign'
+export * from '../../utils/checkType'
+export * from '../../utils/hasProp'
+export * from '../../utils/parseUrl'
+export * from '../../utils/parseUrl-extras'
+export * from '../../utils/isObject'
+export * from '../../utils/virtual-files'
+export * from '../../utils/assertIsNotBrowser'
+export * from '../../utils/isNotNullish'
+export * from '../../utils/unique'
+export * from '../../utils/debug'
diff --git a/vike/node/shared/virtual-files/virtualFileImportUserCode.ts b/vike/node/shared/virtual-files/virtualFileImportUserCode.ts
index 6685b1984f..8a9b9e0031 100644
--- a/vike/node/shared/virtual-files/virtualFileImportUserCode.ts
+++ b/vike/node/shared/virtual-files/virtualFileImportUserCode.ts
@@ -3,7 +3,7 @@ export { virtualFileIdImportUserCodeClientSR }
 export { virtualFileIdImportUserCodeClientCR }
 export { isVirtualFileIdImportUserCode }
 
-import { assert, getVirtualFileId } from '../utils.js'
+import { assert, getVirtualFileId } from '../utils'
 
 const idBase = 'virtual:vike:importUserCode'
 const virtualFileIdImportUserCodeServer = `${idBase}:server`
diff --git a/vike/node/shared/virtual-files/virtualFilePageConfigValuesAll.ts b/vike/node/shared/virtual-files/virtualFilePageConfigValuesAll.ts
index 079b402a04..6996bf4a88 100644
--- a/vike/node/shared/virtual-files/virtualFilePageConfigValuesAll.ts
+++ b/vike/node/shared/virtual-files/virtualFilePageConfigValuesAll.ts
@@ -1,8 +1,8 @@
 export { isVirtualFileIdPageConfigValuesAll }
 export { getVirtualFileIdPageConfigValuesAll }
 
-import { extractAssetsRemoveQuery } from '../extractAssetsQuery.js'
-import { assert, getVirtualFileId } from '../utils.js'
+import { extractAssetsRemoveQuery } from '../extractAssetsQuery'
+import { assert, getVirtualFileId } from '../utils'
 
 const idBase = 'virtual:vike:pageConfigValuesAll:'
 const idBaseClient = `${idBase}client:` as const
diff --git a/vike/shared/RenderErrorPage.ts b/vike/shared/RenderErrorPage.ts
index ddcad84009..b876ceb0d1 100644
--- a/vike/shared/RenderErrorPage.ts
+++ b/vike/shared/RenderErrorPage.ts
@@ -1,2 +1,2 @@
 // TODO/v1-release: remove
-export { RenderErrorPage } from './route/abort.js'
+export { RenderErrorPage } from './route/abort'
diff --git a/vike/shared/abort.ts b/vike/shared/abort.ts
index 51af6fb79b..5da80a8061 100644
--- a/vike/shared/abort.ts
+++ b/vike/shared/abort.ts
@@ -8,4 +8,4 @@
 //   } from 'vike'
 // Use package.json#exports to make the imports isomorphic.
 // The client-side has no utility when using Server Routing.
-export { redirect, render } from './route/abort.js'
+export { redirect, render } from './route/abort'
diff --git a/vike/shared/addIs404ToPageProps.ts b/vike/shared/addIs404ToPageProps.ts
index e8de1d508b..20384ea692 100644
--- a/vike/shared/addIs404ToPageProps.ts
+++ b/vike/shared/addIs404ToPageProps.ts
@@ -1,8 +1,8 @@
 export { addIs404ToPageProps }
 
-import { assert, assertWarning, hasProp, isObject } from './utils.js'
-import { isErrorPage } from './error-page.js'
-import type { PageConfigRuntime } from './page-configs/PageConfig.js'
+import { assert, assertWarning, hasProp, isObject } from './utils'
+import { isErrorPage } from './error-page'
+import type { PageConfigRuntime } from './page-configs/PageConfig'
 
 function addIs404ToPageProps(pageContext: Record<string, unknown> & PageContextAssertIs404) {
   assertIs404(pageContext)
diff --git a/vike/shared/assertHookReturnedObject.ts b/vike/shared/assertHookReturnedObject.ts
index 955bc590c6..62777d894a 100644
--- a/vike/shared/assertHookReturnedObject.ts
+++ b/vike/shared/assertHookReturnedObject.ts
@@ -1,6 +1,6 @@
 export { assertHookReturnedObject }
 
-import { assert, assertUsage, stringifyStringArray } from './utils.js'
+import { assert, assertUsage, stringifyStringArray } from './utils'
 
 function assertHookReturnedObject<Keys extends readonly string[]>(
   obj: Record<string, unknown>,
diff --git a/vike/shared/assertOnBeforeRenderHookReturn.ts b/vike/shared/assertOnBeforeRenderHookReturn.ts
index 9aa140aa2f..e377113ae5 100644
--- a/vike/shared/assertOnBeforeRenderHookReturn.ts
+++ b/vike/shared/assertOnBeforeRenderHookReturn.ts
@@ -1,8 +1,8 @@
 export { assertOnBeforeRenderHookReturn }
 
-import { assertUsage, isPlainObject } from './utils.js'
-import { assertPageContextProvidedByUser } from './assertPageContextProvidedByUser.js'
-import { assertHookReturnedObject } from './assertHookReturnedObject.js'
+import { assertUsage, isPlainObject } from './utils'
+import { assertPageContextProvidedByUser } from './assertPageContextProvidedByUser'
+import { assertHookReturnedObject } from './assertHookReturnedObject'
 import pc from '@brillout/picocolors'
 
 function assertOnBeforeRenderHookReturn<Keys extends readonly string[]>(
diff --git a/vike/shared/assertPageContextProvidedByUser.ts b/vike/shared/assertPageContextProvidedByUser.ts
index 72d197bc7b..7055fcb136 100644
--- a/vike/shared/assertPageContextProvidedByUser.ts
+++ b/vike/shared/assertPageContextProvidedByUser.ts
@@ -1,6 +1,6 @@
 export { assertPageContextProvidedByUser }
 
-import { assert, assertUsage, assertWarning, isObject } from './utils.js'
+import { assert, assertUsage, assertWarning, isObject } from './utils'
 import pc from '@brillout/picocolors'
 
 function assertPageContextProvidedByUser(
diff --git a/vike/shared/assertPageFilePath.ts b/vike/shared/assertPageFilePath.ts
index 5c815decfa..3202bb4436 100644
--- a/vike/shared/assertPageFilePath.ts
+++ b/vike/shared/assertPageFilePath.ts
@@ -2,7 +2,7 @@
 
 export { assertPageFilePath }
 
-import { assertPosixPath } from './utils.js'
+import { assertPosixPath } from './utils'
 
 function assertPageFilePath(filePath: string): void {
   assertPosixPath(filePath)
diff --git a/vike/shared/determinePageIdOld.ts b/vike/shared/determinePageIdOld.ts
index 982546e1df..4333a9eeb8 100644
--- a/vike/shared/determinePageIdOld.ts
+++ b/vike/shared/determinePageIdOld.ts
@@ -1,6 +1,6 @@
 export { determinePageIdOld }
 
-import { slice, assert } from './utils.js'
+import { slice, assert } from './utils'
 
 // TODO/v1-release: remove
 function determinePageIdOld(filePath: string): string {
diff --git a/vike/shared/error-page.ts b/vike/shared/error-page.ts
index 84f38ad385..ed9ca392d3 100644
--- a/vike/shared/error-page.ts
+++ b/vike/shared/error-page.ts
@@ -4,9 +4,9 @@ export { isErrorPage }
 
 // TODO/v1-release: consider loading this file only for Client Routing
 
-import { assert, assertUsage, unique } from './utils.js'
-import type { PageConfigRuntime } from './page-configs/PageConfig.js'
-import type { PageFile } from './getPageFiles.js'
+import { assert, assertUsage, unique } from './utils'
+import type { PageConfigRuntime } from './page-configs/PageConfig'
+import type { PageFile } from './getPageFiles'
 
 function getErrorPageId(pageFilesAll: PageFile[], pageConfigs: PageConfigRuntime[]): string | null {
   if (pageConfigs.length > 0) {
diff --git a/vike/shared/getPageContext.ts b/vike/shared/getPageContext.ts
index a4b37b3f5e..dce085fcd8 100644
--- a/vike/shared/getPageContext.ts
+++ b/vike/shared/getPageContext.ts
@@ -1 +1 @@
-export { getPageContext, providePageContext } from './hooks/executeHook.js'
+export { getPageContext, providePageContext } from './hooks/executeHook'
diff --git a/vike/shared/getPageContextRequestUrl.ts b/vike/shared/getPageContextRequestUrl.ts
index 191494b813..2193715b89 100644
--- a/vike/shared/getPageContextRequestUrl.ts
+++ b/vike/shared/getPageContextRequestUrl.ts
@@ -3,7 +3,7 @@ export { pageContextJsonFileExtension }
 export { doNotCreateExtraDirectory }
 
 // This module isn't loaded by the client-side of Server Routing => we don't inlcude `urlToFile` to `./utils.ts`
-import { urlToFile } from '../utils/urlToFile.js'
+import { urlToFile } from '../utils/urlToFile'
 
 const pageContextJsonFileExtension = '.pageContext.json'
 // `/some-base-url/index.pageContext.json` instead of `/some-base-url.pageContext.json` in order to comply to common reverse proxy setups, see https://github.com/vikejs/vike/issues/443
diff --git a/vike/shared/getPageContextUrlComputed.ts b/vike/shared/getPageContextUrlComputed.ts
index b65b955bfa..12dd74e84d 100644
--- a/vike/shared/getPageContextUrlComputed.ts
+++ b/vike/shared/getPageContextUrlComputed.ts
@@ -10,7 +10,7 @@ export type { PageContextUrlSource }
 // URLs need to be computed, because the user can modify the URL e.g. with onBeforeRoute() for i18n.
 // =====================
 
-import { objectDefineProperty } from '../utils/objectDefineProperty.js'
+import { objectDefineProperty } from '../utils/objectDefineProperty'
 import {
   assert,
   parseUrl,
@@ -20,7 +20,7 @@ import {
   isBrowser,
   changeEnumerable,
   type UrlPublic
-} from './utils.js'
+} from './utils'
 
 // TODO/v1-release: move pageContext.urlParsed to pageContext.url
 type PageContextUrlComputed = {
diff --git a/vike/shared/getPageFiles.ts b/vike/shared/getPageFiles.ts
index 9f010b410c..721ec133a4 100644
--- a/vike/shared/getPageFiles.ts
+++ b/vike/shared/getPageFiles.ts
@@ -1,10 +1,10 @@
 // Types
-export type { PageFile } from './getPageFiles/getPageFileObject.js'
-export type { ExportsAll, PageContextExports } from './getPageFiles/getExports.js'
+export type { PageFile } from './getPageFiles/getPageFileObject'
+export type { ExportsAll, PageContextExports } from './getPageFiles/getExports'
 
-export { getPageFilesAll } from './getPageFiles/setPageFiles.js'
-export { setPageFiles } from './getPageFiles/setPageFiles.js'
-export { setPageFilesAsync } from './getPageFiles/setPageFiles.js'
-export { getPageFilesClientSide } from './getPageFiles/getAllPageIdFiles.js'
-export { getPageFilesServerSide } from './getPageFiles/getAllPageIdFiles.js'
-export { getPageContextExports } from './getPageFiles/getExports.js'
+export { getPageFilesAll } from './getPageFiles/setPageFiles'
+export { setPageFiles } from './getPageFiles/setPageFiles'
+export { setPageFilesAsync } from './getPageFiles/setPageFiles'
+export { getPageFilesClientSide } from './getPageFiles/getAllPageIdFiles'
+export { getPageFilesServerSide } from './getPageFiles/getAllPageIdFiles'
+export { getPageContextExports } from './getPageFiles/getExports'
diff --git a/vike/shared/getPageFiles/analyzeClientSide.ts b/vike/shared/getPageFiles/analyzeClientSide.ts
index a608cfc408..88d09bd3da 100644
--- a/vike/shared/getPageFiles/analyzeClientSide.ts
+++ b/vike/shared/getPageFiles/analyzeClientSide.ts
@@ -1,9 +1,9 @@
 export { analyzeClientSide }
 
-import { getConfigValueRuntime } from '../page-configs/getConfigValue.js'
-import type { PageConfigRuntime } from '../page-configs/PageConfig.js'
-import type { PageFile } from './getPageFileObject.js'
-import { analyzePageClientSide } from './analyzePageClientSide.js'
+import { getConfigValueRuntime } from '../page-configs/getConfigValue'
+import type { PageConfigRuntime } from '../page-configs/PageConfig'
+import type { PageFile } from './getPageFileObject'
+import { analyzePageClientSide } from './analyzePageClientSide'
 
 function analyzeClientSide(
   pageConfig: PageConfigRuntime | null,
diff --git a/vike/shared/getPageFiles/analyzePageClientSide.ts b/vike/shared/getPageFiles/analyzePageClientSide.ts
index 0972ddfa3b..9de83e4389 100644
--- a/vike/shared/getPageFiles/analyzePageClientSide.ts
+++ b/vike/shared/getPageFiles/analyzePageClientSide.ts
@@ -2,14 +2,14 @@ export { analyzePageClientSide }
 export { analyzePageClientSideInit }
 export type { AnalysisResult }
 
-import { analyzeExports } from './analyzePageClientSide/analyzeExports.js'
-import { determineClientEntry } from './analyzePageClientSide/determineClientEntry.js'
-import { getPageFilesClientSide } from './getAllPageIdFiles.js'
-import { getPageFilesServerSide } from './getAllPageIdFiles.js'
-import { assert } from '../utils.js'
-import { getExportNames } from './analyzePageClientSide/getExportNames.js'
-import type { PageFile } from './getPageFileObject.js'
-import type { ClientDependency } from './analyzePageClientSide/ClientDependency.js'
+import { analyzeExports } from './analyzePageClientSide/analyzeExports'
+import { determineClientEntry } from './analyzePageClientSide/determineClientEntry'
+import { getPageFilesClientSide } from './getAllPageIdFiles'
+import { getPageFilesServerSide } from './getAllPageIdFiles'
+import { assert } from '../utils'
+import { getExportNames } from './analyzePageClientSide/getExportNames'
+import type { PageFile } from './getPageFileObject'
+import type { ClientDependency } from './analyzePageClientSide/ClientDependency'
 
 type AnalysisResult = {
   isHtmlOnly: boolean
diff --git a/vike/shared/getPageFiles/analyzePageClientSide/analyzeExports.ts b/vike/shared/getPageFiles/analyzePageClientSide/analyzeExports.ts
index 27741b5aa9..a65b085f0d 100644
--- a/vike/shared/getPageFiles/analyzePageClientSide/analyzeExports.ts
+++ b/vike/shared/getPageFiles/analyzePageClientSide/analyzeExports.ts
@@ -1,8 +1,8 @@
 export { analyzeExports }
 
-import { getExportNames } from './getExportNames.js'
-import { assertUsage } from '../../utils.js'
-import type { PageFile } from '../getPageFileObject.js'
+import { getExportNames } from './getExportNames'
+import { assertUsage } from '../../utils'
+import type { PageFile } from '../getPageFileObject'
 
 // TODO/v1-release: remove
 function analyzeExports({
diff --git a/vike/shared/getPageFiles/analyzePageClientSide/determineClientEntry.ts b/vike/shared/getPageFiles/analyzePageClientSide/determineClientEntry.ts
index 4e7cf1db8e..0c6af5a839 100644
--- a/vike/shared/getPageFiles/analyzePageClientSide/determineClientEntry.ts
+++ b/vike/shared/getPageFiles/analyzePageClientSide/determineClientEntry.ts
@@ -3,8 +3,8 @@
 export { determineClientEntry }
 export { getVikeClientEntry }
 
-import type { ClientDependency } from './ClientDependency.js'
-import type { PageFile } from '../../../shared/getPageFiles.js'
+import type { ClientDependency } from './ClientDependency'
+import type { PageFile } from '../../../shared/getPageFiles'
 
 function determineClientEntry({
   pageFilesClientSide,
diff --git a/vike/shared/getPageFiles/analyzePageClientSide/getExportNames.ts b/vike/shared/getPageFiles/analyzePageClientSide/getExportNames.ts
index be1f624c4a..0cf06f06d7 100644
--- a/vike/shared/getPageFiles/analyzePageClientSide/getExportNames.ts
+++ b/vike/shared/getPageFiles/analyzePageClientSide/getExportNames.ts
@@ -1,7 +1,7 @@
 export { getExportNames }
 
-import { assert } from '../../utils.js'
-import type { PageFile } from '../getPageFileObject.js'
+import { assert } from '../../utils'
+import type { PageFile } from '../getPageFileObject'
 
 function getExportNames(p: PageFile): string[] {
   if (p.fileType === '.css') {
diff --git a/vike/shared/getPageFiles/analyzePageServerSide.ts b/vike/shared/getPageFiles/analyzePageServerSide.ts
index 2b375de9fb..b3fe112533 100644
--- a/vike/shared/getPageFiles/analyzePageServerSide.ts
+++ b/vike/shared/getPageFiles/analyzePageServerSide.ts
@@ -1,8 +1,8 @@
 export { analyzePageServerSide }
 
-import { assert } from '../utils.js'
-import { getPageFilesServerSide } from './getAllPageIdFiles.js'
-import type { PageFile } from './getPageFileObject.js'
+import { assert } from '../utils'
+import { getPageFilesServerSide } from './getAllPageIdFiles'
+import type { PageFile } from './getPageFileObject'
 
 async function analyzePageServerSide(pageFilesAll: PageFile[], pageId: string) {
   const pageFilesServerSide = getPageFilesServerSide(pageFilesAll, pageId)
diff --git a/vike/shared/getPageFiles/assert_exports_old_design.ts b/vike/shared/getPageFiles/assert_exports_old_design.ts
index 7c0d70d1ca..7d634b3543 100644
--- a/vike/shared/getPageFiles/assert_exports_old_design.ts
+++ b/vike/shared/getPageFiles/assert_exports_old_design.ts
@@ -4,8 +4,8 @@ export { assertDefaultExports }
 export { assertExportValues }
 export { forbiddenDefaultExports }
 
-import { assert, assertUsage } from '../utils.js'
-import type { PageFile } from './getPageFileObject.js'
+import { assert, assertUsage } from '../utils'
+import type { PageFile } from './getPageFileObject'
 
 const enforceTrue = ['clientRouting']
 function assertExportValues(pageFile: PageFile) {
diff --git a/vike/shared/getPageFiles/fileTypes.ts b/vike/shared/getPageFiles/fileTypes.ts
index ceb6493e0b..e7efec03eb 100644
--- a/vike/shared/getPageFiles/fileTypes.ts
+++ b/vike/shared/getPageFiles/fileTypes.ts
@@ -5,8 +5,8 @@ export { fileTypes }
 export { isValidFileType }
 export { determineFileType }
 
-import { assert, assertPosixPath } from '../utils.js'
-import { isScriptFile } from '../../utils/isScriptFile.js'
+import { assert, assertPosixPath } from '../utils'
+import { isScriptFile } from '../../utils/isScriptFile'
 
 const fileTypes = [
   '.page',
diff --git a/vike/shared/getPageFiles/getAllPageIdFiles.ts b/vike/shared/getPageFiles/getAllPageIdFiles.ts
index 5b79674c9c..bb6883a4bc 100644
--- a/vike/shared/getPageFiles/getAllPageIdFiles.ts
+++ b/vike/shared/getPageFiles/getAllPageIdFiles.ts
@@ -3,9 +3,9 @@
 export { getPageFilesClientSide }
 export { getPageFilesServerSide }
 
-import { assert, assertUsage, isNotNullish } from '../utils.js'
-import { assertPageFilePath } from '../assertPageFilePath.js'
-import type { PageFile } from './getPageFileObject.js'
+import { assert, assertUsage, isNotNullish } from '../utils'
+import { assertPageFilePath } from '../assertPageFilePath'
+import type { PageFile } from './getPageFileObject'
 
 function getPageFilesClientSide(pageFilesAll: PageFile[], pageId: string): PageFile[] {
   return determine(pageFilesAll, pageId, true)
diff --git a/vike/shared/getPageFiles/getExports.ts b/vike/shared/getPageFiles/getExports.ts
index 92fa36c5b8..7b257d994e 100644
--- a/vike/shared/getPageFiles/getExports.ts
+++ b/vike/shared/getPageFiles/getExports.ts
@@ -6,18 +6,18 @@ export type { From }
 export type { Sources }
 export type { Source }
 
-import { isScriptFile, isTemplateFile } from '../../utils/isScriptFile.js'
-import { assert, isObject, assertWarning, assertUsage, makeLast, isBrowser } from '../utils.js'
-import { assertDefaultExports, forbiddenDefaultExports } from './assert_exports_old_design.js'
-import type { FileType } from './fileTypes.js'
-import type { PageConfigRuntimeLoaded } from './../page-configs/PageConfig.js'
-import type { PageFile } from './getPageFileObject.js'
+import { isScriptFile, isTemplateFile } from '../../utils/isScriptFile'
+import { assert, isObject, assertWarning, assertUsage, makeLast, isBrowser } from '../utils'
+import { assertDefaultExports, forbiddenDefaultExports } from './assert_exports_old_design'
+import type { FileType } from './fileTypes'
+import type { PageConfigRuntimeLoaded } from './../page-configs/PageConfig'
+import type { PageFile } from './getPageFileObject'
 import {
   type ConfigDefinedAtOptional,
   getConfigDefinedAtOptional,
   getDefinedAtString
-} from '../page-configs/getConfigDefinedAt.js'
-import { getConfigValueFilePathToShowToUser } from '../page-configs/helpers.js'
+} from '../page-configs/getConfigDefinedAt'
+import { getConfigValueFilePathToShowToUser } from '../page-configs/helpers'
 import pc from '@brillout/picocolors'
 
 // TODO/v1-release: remove
diff --git a/vike/shared/getPageFiles/getPageFileObject.ts b/vike/shared/getPageFiles/getPageFileObject.ts
index 7459c5ea48..9d42c29fdd 100644
--- a/vike/shared/getPageFiles/getPageFileObject.ts
+++ b/vike/shared/getPageFiles/getPageFileObject.ts
@@ -3,11 +3,11 @@
 export { getPageFileObject }
 export type { PageFile }
 
-import { determinePageIdOld } from '../determinePageIdOld.js'
-import { assertPageFilePath } from '../assertPageFilePath.js'
-import { isErrorPageId } from '../error-page.js'
-import { assert, slice } from '../utils.js'
-import { determineFileType, FileType } from './fileTypes.js'
+import { determinePageIdOld } from '../determinePageIdOld'
+import { assertPageFilePath } from '../assertPageFilePath'
+import { isErrorPageId } from '../error-page'
+import { assert, slice } from '../utils'
+import { determineFileType, FileType } from './fileTypes'
 
 type PageFile = {
   filePath: string
diff --git a/vike/shared/getPageFiles/parseGlobResults.ts b/vike/shared/getPageFiles/parseGlobResults.ts
index a0a3cb4113..b860c97638 100644
--- a/vike/shared/getPageFiles/parseGlobResults.ts
+++ b/vike/shared/getPageFiles/parseGlobResults.ts
@@ -2,16 +2,16 @@ export { parseGlobResults }
 
 // TODO/v1-release: remove old design code, and remove all assertions.
 
-import { assert, hasProp, isCallable, isObject, cast, isArray } from '../utils.js'
-import { assertExportValues } from './assert_exports_old_design.js'
-import { getPageFileObject, type PageFile } from './getPageFileObject.js'
-import { fileTypes, type FileType } from './fileTypes.js'
-import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../page-configs/PageConfig.js'
-import { parsePageConfigs } from '../page-configs/serialize/parsePageConfigs.js'
+import { assert, hasProp, isCallable, isObject, cast, isArray } from '../utils'
+import { assertExportValues } from './assert_exports_old_design'
+import { getPageFileObject, type PageFile } from './getPageFileObject'
+import { fileTypes, type FileType } from './fileTypes'
+import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../page-configs/PageConfig'
+import { parsePageConfigs } from '../page-configs/serialize/parsePageConfigs'
 import type {
   PageConfigGlobalRuntimeSerialized,
   PageConfigRuntimeSerialized
-} from '../page-configs/serialize/PageConfigSerialized.js'
+} from '../page-configs/serialize/PageConfigSerialized'
 
 function parseGlobResults(pageFilesExports: unknown): {
   pageFiles: PageFile[]
diff --git a/vike/shared/getPageFiles/setPageFiles.ts b/vike/shared/getPageFiles/setPageFiles.ts
index e3e798ecae..b0308b14f7 100644
--- a/vike/shared/getPageFiles/setPageFiles.ts
+++ b/vike/shared/getPageFiles/setPageFiles.ts
@@ -2,11 +2,11 @@ export { setPageFiles }
 export { setPageFilesAsync }
 export { getPageFilesAll }
 
-import { assert, unique } from '../utils.js'
-import type { PageFile } from './getPageFileObject.js'
-import { parseGlobResults } from './parseGlobResults.js'
-import { getGlobalObject } from '../../utils/getGlobalObject.js'
-import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../page-configs/PageConfig.js'
+import { assert, unique } from '../utils'
+import type { PageFile } from './getPageFileObject'
+import { parseGlobResults } from './parseGlobResults'
+import { getGlobalObject } from '../../utils/getGlobalObject'
+import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../page-configs/PageConfig'
 
 const globalObject = getGlobalObject<{
   pageFilesAll?: PageFile[] | undefined
diff --git a/vike/shared/hooks/executeHook.ts b/vike/shared/hooks/executeHook.ts
index 204f796113..ec37bfce37 100644
--- a/vike/shared/hooks/executeHook.ts
+++ b/vike/shared/hooks/executeHook.ts
@@ -3,12 +3,12 @@ export { getPageContext }
 export { providePageContext }
 export { isUserHookError }
 
-import { getProjectError, assertWarning } from '../../utils/assert.js'
-import { getGlobalObject } from '../../utils/getGlobalObject.js'
-import { humanizeTime } from '../../utils/humanizeTime.js'
-import { isObject } from '../../utils/isObject.js'
-import type { PageContextClient, PageContextServer } from '../types.js'
-import type { Hook, HookLoc } from './getHook.js'
+import { getProjectError, assertWarning } from '../../utils/assert'
+import { getGlobalObject } from '../../utils/getGlobalObject'
+import { humanizeTime } from '../../utils/humanizeTime'
+import { isObject } from '../../utils/isObject'
+import type { PageContextClient, PageContextServer } from '../types'
+import type { Hook, HookLoc } from './getHook'
 const globalObject = getGlobalObject('utils/executeHook.ts', {
   userHookErrors: new WeakMap<object, HookLoc>(),
   pageContext: null as PageContextUnknown
diff --git a/vike/shared/hooks/getHook.ts b/vike/shared/hooks/getHook.ts
index 478fe39d31..c471fd0871 100644
--- a/vike/shared/hooks/getHook.ts
+++ b/vike/shared/hooks/getHook.ts
@@ -13,13 +13,13 @@ export type { HooksTimeoutProvidedByUser }
 // We export for old V0.4 design which doesn't support configooksTimeout
 export { getHookTimeoutDefault }
 
-import { getGlobalObject } from '../../utils/getGlobalObject.js'
-import type { PageContextExports } from '../getPageFiles.js'
-import type { HookName, HookNamePage, HookNameGlobal } from '../page-configs/Config.js'
-import type { PageConfigGlobalRuntime, PageConfigRuntime } from '../page-configs/PageConfig.js'
-import { getHookFilePathToShowToUser } from '../page-configs/helpers.js'
-import { getConfigValueRuntime } from '../page-configs/getConfigValue.js'
-import { assert, assertUsage, checkType, isCallable, isObject } from '../utils.js'
+import { getGlobalObject } from '../../utils/getGlobalObject'
+import type { PageContextExports } from '../getPageFiles'
+import type { HookName, HookNamePage, HookNameGlobal } from '../page-configs/Config'
+import type { PageConfigGlobalRuntime, PageConfigRuntime } from '../page-configs/PageConfig'
+import { getHookFilePathToShowToUser } from '../page-configs/helpers'
+import { getConfigValueRuntime } from '../page-configs/getConfigValue'
+import { assert, assertUsage, checkType, isCallable, isObject } from '../utils'
 import pc from '@brillout/picocolors'
 const globalObject = getGlobalObject<{ isPrerendering?: true }>('getHook.ts', {})
 
diff --git a/vike/shared/modifyUrl.ts b/vike/shared/modifyUrl.ts
index 461528fd6c..7ba62c7ba4 100644
--- a/vike/shared/modifyUrl.ts
+++ b/vike/shared/modifyUrl.ts
@@ -1,6 +1,6 @@
 export { modifyUrl }
 
-import { createUrlFromComponents, parseUrl } from './utils.js'
+import { createUrlFromComponents, parseUrl } from './utils'
 
 /**
  * Modify a URL.
diff --git a/vike/shared/page-configs/Config.ts b/vike/shared/page-configs/Config.ts
index af18f91ee9..1e0d9a8f6e 100644
--- a/vike/shared/page-configs/Config.ts
+++ b/vike/shared/page-configs/Config.ts
@@ -36,14 +36,14 @@ export type { KeepScrollPosition }
 import type {
   PrefetchSetting,
   PrefetchStaticAssets
-} from '../../client/client-routing-runtime/prefetch/PrefetchSetting.js'
-import type { ConfigDefinition } from '../../node/plugin/plugins/importUserCode/v1-design/getVikeConfig/configDefinitionsBuiltIn.js'
-import type { DocumentHtml } from '../../node/runtime/html/renderHtml.js'
-import type { InjectFilterEntry } from '../../types/index.js'
-import type { ConfigVikeUserProvided } from '../ConfigVike.js'
-import type { Vike, VikePackages } from '../VikeNamespace.js'
-import type { HooksTimeoutProvidedByUser } from '../hooks/getHook.js'
-import type { PageContextClient, PageContextServer } from '../types.js'
+} from '../../client/client-routing-runtime/prefetch/PrefetchSetting'
+import type { ConfigDefinition } from '../../node/plugin/plugins/importUserCode/v1-design/getVikeConfig/configDefinitionsBuiltIn'
+import type { DocumentHtml } from '../../node/runtime/html/renderHtml'
+import type { InjectFilterEntry } from '../../types/index'
+import type { ConfigVikeUserProvided } from '../ConfigVike'
+import type { Vike, VikePackages } from '../VikeNamespace'
+import type { HooksTimeoutProvidedByUser } from '../hooks/getHook'
+import type { PageContextClient, PageContextServer } from '../types'
 
 type HookName = HookNamePage | HookNameGlobal | HookNameOldDesign
 type HookNamePage =
diff --git a/vike/shared/page-configs/Config/PageContextConfig.ts b/vike/shared/page-configs/Config/PageContextConfig.ts
index 00d716163d..de6701b514 100644
--- a/vike/shared/page-configs/Config/PageContextConfig.ts
+++ b/vike/shared/page-configs/Config/PageContextConfig.ts
@@ -1,8 +1,8 @@
 export type { PageContextConfig }
 
-import type { VikePackages } from '../../VikeNamespace.js'
-import type { ConfigBuiltIn, ImportString } from '../Config.js'
-import type { Combine, IsNotEmpty, XOR5 } from './helpers.js'
+import type { VikePackages } from '../../VikeNamespace'
+import type { ConfigBuiltIn, ImportString } from '../Config'
+import type { Combine, IsNotEmpty, XOR5 } from './helpers'
 
 type WithoutImportString<T> = { [K in keyof T]: Exclude<T[K], ImportString> }
 
diff --git a/vike/shared/page-configs/PageConfig.ts b/vike/shared/page-configs/PageConfig.ts
index 66897e0910..c90b2bd308 100644
--- a/vike/shared/page-configs/PageConfig.ts
+++ b/vike/shared/page-configs/PageConfig.ts
@@ -17,10 +17,10 @@ export type { DefinedAtData }
 export type { DefinedAtFile }
 export type { DefinedAtFilePath }
 
-import type { ConfigValueSerialized } from './serialize/PageConfigSerialized.js'
-import type { LocationId } from '../../node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting.js'
-import type { FilePath } from './FilePath.js'
-import type { ConfigDefinitions } from '../../node/plugin/plugins/importUserCode/v1-design/getVikeConfig/configDefinitionsBuiltIn.js'
+import type { ConfigValueSerialized } from './serialize/PageConfigSerialized'
+import type { LocationId } from '../../node/plugin/plugins/importUserCode/v1-design/getVikeConfig/filesystemRouting'
+import type { FilePath } from './FilePath'
+import type { ConfigDefinitions } from '../../node/plugin/plugins/importUserCode/v1-design/getVikeConfig/configDefinitionsBuiltIn'
 
 type PageConfigBase = {
   pageId: string
diff --git a/vike/shared/page-configs/assertPlusFileExport.ts b/vike/shared/page-configs/assertPlusFileExport.ts
index 411a6d4b3a..7e511730de 100644
--- a/vike/shared/page-configs/assertPlusFileExport.ts
+++ b/vike/shared/page-configs/assertPlusFileExport.ts
@@ -1,6 +1,6 @@
 export { assertPlusFileExport }
 
-import { assert, assertUsage, assertWarning } from '../utils.js'
+import { assert, assertUsage, assertWarning } from '../utils'
 import pc from '@brillout/picocolors'
 
 const EXPORTS_IGNORE = [
diff --git a/vike/shared/page-configs/findPageConfig.ts b/vike/shared/page-configs/findPageConfig.ts
index ae787e40b7..6002b70268 100644
--- a/vike/shared/page-configs/findPageConfig.ts
+++ b/vike/shared/page-configs/findPageConfig.ts
@@ -1,7 +1,7 @@
 export { findPageConfig }
 
-import { assert } from '../utils.js'
-import type { PageConfigRuntime } from './PageConfig.js'
+import { assert } from '../utils'
+import type { PageConfigRuntime } from './PageConfig'
 
 function findPageConfig(pageConfigs: PageConfigRuntime[], pageId: string): null | PageConfigRuntime {
   const result = pageConfigs.filter((p) => p.pageId === pageId)
diff --git a/vike/shared/page-configs/getConfigDefinedAt.ts b/vike/shared/page-configs/getConfigDefinedAt.ts
index 93495c3c56..d4279094da 100644
--- a/vike/shared/page-configs/getConfigDefinedAt.ts
+++ b/vike/shared/page-configs/getConfigDefinedAt.ts
@@ -4,10 +4,10 @@ export { getDefinedAtString }
 export type { ConfigDefinedAt }
 export type { ConfigDefinedAtOptional }
 
-import { assert, isArray } from '../utils.js'
-import type { DefinedAtData, DefinedAtFile } from './PageConfig.js'
+import { assert, isArray } from '../utils'
+import type { DefinedAtData, DefinedAtFile } from './PageConfig'
 import pc from '@brillout/picocolors'
-import { getExportPath } from './getExportPath.js'
+import { getExportPath } from './getExportPath'
 
 type ConfigDefinedAtOptional = ConfigDefinedAt | `Config ${string} defined internally`
 type ConfigDefinedAt = `Config ${string} defined at ${string}`
diff --git a/vike/shared/page-configs/getConfigValue.ts b/vike/shared/page-configs/getConfigValue.ts
index f2f7ffe0d8..c750407426 100644
--- a/vike/shared/page-configs/getConfigValue.ts
+++ b/vike/shared/page-configs/getConfigValue.ts
@@ -2,11 +2,11 @@ export { getConfigValueRuntime }
 export { getConfigValueTyped }
 export type { TypeAsString }
 
-import { type ResolveTypeAsString, assert, assertUsage, getValuePrintable } from '../utils.js'
-import type { PageConfigRuntime, ConfigValue, DefinedAtData } from './PageConfig.js'
-import type { ConfigNameBuiltIn } from './Config.js'
+import { type ResolveTypeAsString, assert, assertUsage, getValuePrintable } from '../utils'
+import type { PageConfigRuntime, ConfigValue, DefinedAtData } from './PageConfig'
+import type { ConfigNameBuiltIn } from './Config'
 import pc from '@brillout/picocolors'
-import { getConfigDefinedAtOptional } from './getConfigDefinedAt.js'
+import { getConfigDefinedAtOptional } from './getConfigDefinedAt'
 type ConfigName = ConfigNameBuiltIn
 type TypeAsString = 'string' | 'boolean' | undefined
 
diff --git a/vike/shared/page-configs/getConfigValueBuildTime.ts b/vike/shared/page-configs/getConfigValueBuildTime.ts
index 1faa8a79dc..450fc0db26 100644
--- a/vike/shared/page-configs/getConfigValueBuildTime.ts
+++ b/vike/shared/page-configs/getConfigValueBuildTime.ts
@@ -1,10 +1,10 @@
 export { getConfigValueBuildTime }
 
-import { assert, type ResolveTypeAsString } from '../utils.js'
-import type { PageConfigBuildTime, ConfigValue, ConfigValueSource, DefinedAtFile } from './PageConfig.js'
-import type { ConfigNameBuiltIn } from './Config.js'
-import { getConfigValueTyped, type TypeAsString } from './getConfigValue.js'
-import { assertIsNotProductionRuntime } from '../../utils/assertIsNotProductionRuntime.js'
+import { assert, type ResolveTypeAsString } from '../utils'
+import type { PageConfigBuildTime, ConfigValue, ConfigValueSource, DefinedAtFile } from './PageConfig'
+import type { ConfigNameBuiltIn } from './Config'
+import { getConfigValueTyped, type TypeAsString } from './getConfigValue'
+import { assertIsNotProductionRuntime } from '../../utils/assertIsNotProductionRuntime'
 assertIsNotProductionRuntime()
 type ConfigName = ConfigNameBuiltIn
 
diff --git a/vike/shared/page-configs/getExportPath.spec.ts b/vike/shared/page-configs/getExportPath.spec.ts
index a9fffffc09..37017c07e6 100644
--- a/vike/shared/page-configs/getExportPath.spec.ts
+++ b/vike/shared/page-configs/getExportPath.spec.ts
@@ -1,4 +1,4 @@
-import { getExportPath } from './getExportPath.js'
+import { getExportPath } from './getExportPath'
 import { expect, describe, it } from 'vitest'
 
 describe('getExportPath()', () => {
diff --git a/vike/shared/page-configs/getExportPath.ts b/vike/shared/page-configs/getExportPath.ts
index 187984e5a5..d8e0c90dca 100644
--- a/vike/shared/page-configs/getExportPath.ts
+++ b/vike/shared/page-configs/getExportPath.ts
@@ -1,6 +1,6 @@
 export { getExportPath }
 
-import { assert } from '../utils.js'
+import { assert } from '../utils'
 
 function getExportPath(fileExportPathToShowToUser: null | string[], configName: string): null | string {
   if (!fileExportPathToShowToUser) return null
diff --git a/vike/shared/page-configs/helpers.ts b/vike/shared/page-configs/helpers.ts
index cdf68e4c2f..650d49b4c5 100644
--- a/vike/shared/page-configs/helpers.ts
+++ b/vike/shared/page-configs/helpers.ts
@@ -2,8 +2,8 @@ export { getPageConfig }
 export { getConfigValueFilePathToShowToUser }
 export { getHookFilePathToShowToUser }
 
-import { assert, isArray } from '../utils.js'
-import type { PageConfigRuntime, DefinedAtData } from './PageConfig.js'
+import { assert, isArray } from '../utils'
+import type { PageConfigRuntime, DefinedAtData } from './PageConfig'
 
 function getPageConfig(pageId: string, pageConfigs: PageConfigRuntime[]): PageConfigRuntime {
   const pageConfig = pageConfigs.find((p) => p.pageId === pageId)
diff --git a/vike/shared/page-configs/loadConfigValues.ts b/vike/shared/page-configs/loadConfigValues.ts
index e47a0c0b35..c66c9f19f0 100644
--- a/vike/shared/page-configs/loadConfigValues.ts
+++ b/vike/shared/page-configs/loadConfigValues.ts
@@ -1,8 +1,8 @@
 export { loadConfigValues }
 
-import { objectAssign } from '../utils.js'
-import type { PageConfigRuntime, PageConfigRuntimeLoaded } from './PageConfig.js'
-import { parseConfigValuesSerialized } from './serialize/parsePageConfigs.js'
+import { objectAssign } from '../utils'
+import type { PageConfigRuntime, PageConfigRuntimeLoaded } from './PageConfig'
+import { parseConfigValuesSerialized } from './serialize/parsePageConfigs'
 
 async function loadConfigValues(pageConfig: PageConfigRuntime, isDev: boolean): Promise<PageConfigRuntimeLoaded> {
   if (
diff --git a/vike/shared/page-configs/serialize/PageConfigSerialized.ts b/vike/shared/page-configs/serialize/PageConfigSerialized.ts
index ebcc6ead24..f9e6300923 100644
--- a/vike/shared/page-configs/serialize/PageConfigSerialized.ts
+++ b/vike/shared/page-configs/serialize/PageConfigSerialized.ts
@@ -8,7 +8,7 @@ import type {
   ConfigValueComputed,
   ConfigValueCumulative,
   PageConfigRuntime
-} from '../PageConfig.js'
+} from '../PageConfig'
 
 /** Page config data structure serialized in virtual files: parsing it results in PageConfigRuntime */
 type PageConfigRuntimeSerialized = Omit<PageConfigRuntime, 'configValues'> & {
diff --git a/vike/shared/page-configs/serialize/parsePageConfigs.ts b/vike/shared/page-configs/serialize/parsePageConfigs.ts
index 3056e5727d..2e36ba504c 100644
--- a/vike/shared/page-configs/serialize/parsePageConfigs.ts
+++ b/vike/shared/page-configs/serialize/parsePageConfigs.ts
@@ -7,17 +7,17 @@ import type {
   PageConfigGlobalRuntime,
   ConfigValue,
   DefinedAtFile
-} from '../PageConfig.js'
+} from '../PageConfig'
 import type {
   PageConfigGlobalRuntimeSerialized,
   PageConfigRuntimeSerialized,
   ValueSerialized
-} from './PageConfigSerialized.js'
-import { assert, assertUsage, isCallable } from '../../utils.js'
-import { getConfigDefinedAt } from '../getConfigDefinedAt.js'
-import type { ConfigValueSerialized } from './PageConfigSerialized.js'
+} from './PageConfigSerialized'
+import { assert, assertUsage, isCallable } from '../../utils'
+import { getConfigDefinedAt } from '../getConfigDefinedAt'
+import type { ConfigValueSerialized } from './PageConfigSerialized'
 import { parseTransform } from '@brillout/json-serializer/parse'
-import { assertPlusFileExport } from '../assertPlusFileExport.js'
+import { assertPlusFileExport } from '../assertPlusFileExport'
 
 function parseConfigValuesSerialized(configValuesSerialized: Record<string, ConfigValueSerialized>): ConfigValues {
   const configValues = parseConfigValuesSerialized_tmp(configValuesSerialized)
diff --git a/vike/shared/page-configs/serialize/serializeConfigValues.ts b/vike/shared/page-configs/serialize/serializeConfigValues.ts
index 11130e7a22..d1bd9b5c78 100644
--- a/vike/shared/page-configs/serialize/serializeConfigValues.ts
+++ b/vike/shared/page-configs/serialize/serializeConfigValues.ts
@@ -1,7 +1,7 @@
 export { serializeConfigValues }
 
-import { assertIsNotProductionRuntime } from '../../../utils/assertIsNotProductionRuntime.js'
-import { assert, assertUsage, getPropAccessNotation } from '../../../node/plugin/utils.js'
+import { assertIsNotProductionRuntime } from '../../../utils/assertIsNotProductionRuntime'
+import { assert, assertUsage, getPropAccessNotation } from '../../../node/plugin/utils'
 import type {
   ConfigEnvInternal,
   ConfigValue,
@@ -10,11 +10,11 @@ import type {
   DefinedAtFile,
   PageConfigBuildTime,
   PageConfigGlobalBuildTime
-} from '../PageConfig.js'
-import type { ValueSerialized } from './PageConfigSerialized.js'
-import { addImportStatement } from '../../../node/plugin/plugins/importUserCode/addImportStatement.js'
-import { parsePointerImportData } from '../../../node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports.js'
-import { getConfigValueFilePathToShowToUser } from '../helpers.js'
+} from '../PageConfig'
+import type { ValueSerialized } from './PageConfigSerialized'
+import { addImportStatement } from '../../../node/plugin/plugins/importUserCode/addImportStatement'
+import { parsePointerImportData } from '../../../node/plugin/plugins/importUserCode/v1-design/getVikeConfig/transformPointerImports'
+import { getConfigValueFilePathToShowToUser } from '../helpers'
 import { stringify } from '@brillout/json-serializer/stringify'
 import pc from '@brillout/picocolors'
 const REPLACE_ME_BEFORE = '__VIKE__REPLACE_ME_BEFORE__'
@@ -216,7 +216,7 @@ function valueToJson(
       // - We don't need this anymore and could remove it.
       //   - We temporarily needed it for nested document configs (`config.document.{title,description,favicon}`), but we finally decided to go for flat document configs instead (`config.{title,description,favicon}`).
       //   - https://github.com/vikejs/vike-react/pull/113
-      replacer(_, value) {
+      replacer(_: unknown, value: string) {
         if (typeof value === 'string') {
           const importData = parsePointerImportData(value)
           if (importData) {
diff --git a/vike/shared/preparePageContextForUserConsumption.ts b/vike/shared/preparePageContextForUserConsumption.ts
index 26c4fe6496..ffdef6c0bb 100644
--- a/vike/shared/preparePageContextForUserConsumption.ts
+++ b/vike/shared/preparePageContextForUserConsumption.ts
@@ -1,9 +1,9 @@
 export { preparePageContextForUserConsumption }
 
-import { assert, assertWarning, compareString } from './utils.js'
-import type { PageContextForUserConsumptionClientSide } from '../client/shared/preparePageContextForUserConsumptionClientSide.js'
-import type { PageContextForUserConsumptionServerSide } from '../node/runtime/renderPage/preparePageContextForUserConsumptionServerSide.js'
-import { addIs404ToPageProps } from './addIs404ToPageProps.js'
+import { assert, assertWarning, compareString } from './utils'
+import type { PageContextForUserConsumptionClientSide } from '../client/shared/preparePageContextForUserConsumptionClientSide'
+import type { PageContextForUserConsumptionServerSide } from '../node/runtime/renderPage/preparePageContextForUserConsumptionServerSide'
+import { addIs404ToPageProps } from './addIs404ToPageProps'
 
 type PageContextForUserConsumption = PageContextForUserConsumptionServerSide | PageContextForUserConsumptionClientSide
 
diff --git a/vike/shared/route/abort.ts b/vike/shared/route/abort.ts
index 8f25305867..41a3de0cbf 100644
--- a/vike/shared/route/abort.ts
+++ b/vike/shared/route/abort.ts
@@ -13,7 +13,7 @@ export type { ErrorAbort }
 export type { PageContextFromRewrite }
 export type { UrlRedirect }
 
-import { isUserHookError } from '../hooks/executeHook.js'
+import { isUserHookError } from '../hooks/executeHook'
 import {
   assert,
   assertInfo,
@@ -26,7 +26,7 @@ import {
   joinEnglish,
   objectAssign,
   truncateString
-} from './utils.js'
+} from './utils'
 import pc from '@brillout/picocolors'
 
 type RedirectStatusCode = number &
diff --git a/vike/shared/route/debug.ts b/vike/shared/route/debug.ts
index a1f132da72..fbeb080ff9 100644
--- a/vike/shared/route/debug.ts
+++ b/vike/shared/route/debug.ts
@@ -1,7 +1,7 @@
 export { debug }
 
 // Note how we only import `type`: we don't actually import/load the debug code.
-import type { createDebugger, Debug } from '../../utils/debug.js'
+import type { createDebugger, Debug } from '../../utils/debug'
 
 var _debug: undefined | typeof debug
 function debug(...args: Parameters<Debug>) {
diff --git a/vike/shared/route/deduceRouteStringFromFilesystemPath.spec.ts b/vike/shared/route/deduceRouteStringFromFilesystemPath.spec.ts
index 89e56b6e11..b33024dc25 100644
--- a/vike/shared/route/deduceRouteStringFromFilesystemPath.spec.ts
+++ b/vike/shared/route/deduceRouteStringFromFilesystemPath.spec.ts
@@ -1,4 +1,4 @@
-import { deduceRouteStringFromFilesystemPath } from './deduceRouteStringFromFilesystemPath.js'
+import { deduceRouteStringFromFilesystemPath } from './deduceRouteStringFromFilesystemPath'
 import { expect, describe, it } from 'vitest'
 
 describe('deduceRouteStringFromFilesystemPath', () => {
diff --git a/vike/shared/route/deduceRouteStringFromFilesystemPath.ts b/vike/shared/route/deduceRouteStringFromFilesystemPath.ts
index dd4be560fd..a7a759dcbf 100644
--- a/vike/shared/route/deduceRouteStringFromFilesystemPath.ts
+++ b/vike/shared/route/deduceRouteStringFromFilesystemPath.ts
@@ -1,6 +1,6 @@
 // Unit tests at ./deduceRouteStringFromFilesystemPath.spec.ts
 
-import { assert, higherFirst, slice } from './utils.js'
+import { assert, higherFirst, slice } from './utils'
 
 export { deduceRouteStringFromFilesystemPath }
 export type { FilesystemRoot }
diff --git a/vike/shared/route/executeGuardHook.ts b/vike/shared/route/executeGuardHook.ts
index 9dbbfbd606..79ce18f5ef 100644
--- a/vike/shared/route/executeGuardHook.ts
+++ b/vike/shared/route/executeGuardHook.ts
@@ -1,10 +1,10 @@
 export { executeGuardHook }
 
-import { getHook, getHookTimeoutDefault, type Hook } from '../hooks/getHook.js'
-import { assert, assertUsage, isCallable } from './utils.js'
-import type { PageContextExports, PageFile } from '../getPageFiles.js'
-import type { PageConfigRuntime } from '../page-configs/PageConfig.js'
-import { executeHook } from '../hooks/executeHook.js'
+import { getHook, getHookTimeoutDefault, type Hook } from '../hooks/getHook'
+import { assert, assertUsage, isCallable } from './utils'
+import type { PageContextExports, PageFile } from '../getPageFiles'
+import type { PageConfigRuntime } from '../page-configs/PageConfig'
+import { executeHook } from '../hooks/executeHook'
 const errIntro = 'The guard() hook defined by'
 
 async function executeGuardHook<
diff --git a/vike/shared/route/executeOnBeforeRouteHook.ts b/vike/shared/route/executeOnBeforeRouteHook.ts
index 64561bf9dd..e038fad731 100644
--- a/vike/shared/route/executeOnBeforeRouteHook.ts
+++ b/vike/shared/route/executeOnBeforeRouteHook.ts
@@ -1,6 +1,6 @@
 export { executeOnBeforeRouteHook }
 
-import { assertPageContextProvidedByUser } from '../assertPageContextProvidedByUser.js'
+import { assertPageContextProvidedByUser } from '../assertPageContextProvidedByUser'
 import {
   assertUsage,
   hasProp,
@@ -10,12 +10,12 @@ import {
   assertUsageUrlPathnameAbsolute,
   joinEnglish,
   assert
-} from './utils.js'
-import { assertRouteParams, assertSyncRouting } from './resolveRouteFunction.js'
+} from './utils'
+import { assertRouteParams, assertSyncRouting } from './resolveRouteFunction'
 import pc from '@brillout/picocolors'
-import type { PageContextForRoute, PageContextFromRoute } from './index.js'
-import type { Hook } from '../hooks/getHook.js'
-import { executeHook } from '../hooks/executeHook.js'
+import type { PageContextForRoute, PageContextFromRoute } from './index'
+import type { Hook } from '../hooks/getHook'
+import { executeHook } from '../hooks/executeHook'
 
 async function executeOnBeforeRouteHook(
   pageContext: PageContextForRoute
diff --git a/vike/shared/route/index.ts b/vike/shared/route/index.ts
index 208ad5c37b..51710f0849 100644
--- a/vike/shared/route/index.ts
+++ b/vike/shared/route/index.ts
@@ -5,28 +5,28 @@ export type { PageRoutes }
 export type { RouteMatches }
 
 // Ensure we don't bloat runtime of Server Routing
-import { assertClientRouting } from '../../utils/assertRoutingType.js'
-import { isBrowser } from '../../utils/isBrowser.js'
+import { assertClientRouting } from '../../utils/assertRoutingType'
+import { isBrowser } from '../../utils/isBrowser'
 if (isBrowser()) {
   assertClientRouting()
 }
 
-import type { PageFile } from '../getPageFiles.js'
-import { assert, assertUsage, isPlainObject, objectAssign } from './utils.js'
+import type { PageFile } from '../getPageFiles'
+import { assert, assertUsage, isPlainObject, objectAssign } from './utils'
 import {
   assertPageContextUrl,
   type PageContextUrlInternal,
   type PageContextUrlSource
-} from '../getPageContextUrlComputed.js'
-import { resolvePrecendence } from './resolvePrecedence.js'
-import { resolveRouteString } from './resolveRouteString.js'
-import { resolveRouteFunction } from './resolveRouteFunction.js'
-import { executeOnBeforeRouteHook } from './executeOnBeforeRouteHook.js'
-import type { PageRoutes, RouteType } from './loadPageRoutes.js'
-import { debug } from './debug.js'
-import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../page-configs/PageConfig.js'
+} from '../getPageContextUrlComputed'
+import { resolvePrecendence } from './resolvePrecedence'
+import { resolveRouteString } from './resolveRouteString'
+import { resolveRouteFunction } from './resolveRouteFunction'
+import { executeOnBeforeRouteHook } from './executeOnBeforeRouteHook'
+import type { PageRoutes, RouteType } from './loadPageRoutes'
+import { debug } from './debug'
+import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../page-configs/PageConfig'
 import pc from '@brillout/picocolors'
-import type { Hook } from '../hooks/getHook.js'
+import type { Hook } from '../hooks/getHook'
 
 type PageContextForRoute = PageContextUrlInternal & {
   _pageFilesAll: PageFile[]
diff --git a/vike/shared/route/loadPageRoutes.ts b/vike/shared/route/loadPageRoutes.ts
index 693c46093f..aa9ed27615 100644
--- a/vike/shared/route/loadPageRoutes.ts
+++ b/vike/shared/route/loadPageRoutes.ts
@@ -2,16 +2,16 @@ export { loadPageRoutes }
 export type { PageRoutes }
 export type { RouteType }
 
-import type { PageFile } from '../getPageFiles.js'
-import { isErrorPageId } from '../error-page.js'
-import { assert, assertUsage, hasProp, slice } from './utils.js'
-import { FilesystemRoot, deduceRouteStringFromFilesystemPath } from './deduceRouteStringFromFilesystemPath.js'
-import { isCallable } from '../utils.js'
-import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../page-configs/PageConfig.js'
-import { getConfigValueRuntime } from '../page-configs/getConfigValue.js'
-import { getDefinedAtString } from '../page-configs/getConfigDefinedAt.js'
-import { warnDeprecatedAllowKey } from './resolveRouteFunction.js'
-import { getHookFromPageConfigGlobal, getHookTimeoutDefault, type Hook } from '../hooks/getHook.js'
+import type { PageFile } from '../getPageFiles'
+import { isErrorPageId } from '../error-page'
+import { assert, assertUsage, hasProp, slice } from './utils'
+import { FilesystemRoot, deduceRouteStringFromFilesystemPath } from './deduceRouteStringFromFilesystemPath'
+import { isCallable } from '../utils'
+import type { PageConfigRuntime, PageConfigGlobalRuntime } from '../page-configs/PageConfig'
+import { getConfigValueRuntime } from '../page-configs/getConfigValue'
+import { getDefinedAtString } from '../page-configs/getConfigDefinedAt'
+import { warnDeprecatedAllowKey } from './resolveRouteFunction'
+import { getHookFromPageConfigGlobal, getHookTimeoutDefault, type Hook } from '../hooks/getHook'
 
 type PageRoute = {
   pageId: string
diff --git a/vike/shared/route/resolvePrecedence.ts b/vike/shared/route/resolvePrecedence.ts
index 901b97b1ae..99809fb9de 100644
--- a/vike/shared/route/resolvePrecedence.ts
+++ b/vike/shared/route/resolvePrecedence.ts
@@ -1,11 +1,11 @@
 export { resolvePrecendence }
 // export type { RouteMatch }
 
-import { analyzeRouteString } from './resolveRouteString.js'
-import { higherFirst, lowerFirst } from './utils.js'
-import { makeFirst } from './utils.js'
-import { isStaticRouteString } from './resolveRouteString.js'
-import type { RouteType } from './loadPageRoutes.js'
+import { analyzeRouteString } from './resolveRouteString'
+import { higherFirst, lowerFirst } from './utils'
+import { makeFirst } from './utils'
+import { isStaticRouteString } from './resolveRouteString'
+import type { RouteType } from './loadPageRoutes'
 
 type RouteMatch = {
   precedence?: number | null
diff --git a/vike/shared/route/resolvePrecedence/resolvePrecedence_overall.spec.ts b/vike/shared/route/resolvePrecedence/resolvePrecedence_overall.spec.ts
index e0b39b9050..0222430172 100644
--- a/vike/shared/route/resolvePrecedence/resolvePrecedence_overall.spec.ts
+++ b/vike/shared/route/resolvePrecedence/resolvePrecedence_overall.spec.ts
@@ -1,4 +1,4 @@
-import { resolvePrecendence } from '../resolvePrecedence.js'
+import { resolvePrecendence } from '../resolvePrecedence'
 import { expect, describe, it } from 'vitest'
 
 const routeFilesystemStatic = {
diff --git a/vike/shared/route/resolvePrecedence/resolvePrecedence_route-strings.spec.ts b/vike/shared/route/resolvePrecedence/resolvePrecedence_route-strings.spec.ts
index d294037e92..13c017d4fa 100644
--- a/vike/shared/route/resolvePrecedence/resolvePrecedence_route-strings.spec.ts
+++ b/vike/shared/route/resolvePrecedence/resolvePrecedence_route-strings.spec.ts
@@ -1,5 +1,5 @@
-import { resolvePrecendence } from '../resolvePrecedence.js'
-import { resolveRouteString } from '../resolveRouteString.js'
+import { resolvePrecendence } from '../resolvePrecedence'
+import { resolveRouteString } from '../resolveRouteString'
 import { expect, describe, it } from 'vitest'
 
 describe('Route Strings Precedence', () => {
diff --git a/vike/shared/route/resolveRoute.ts b/vike/shared/route/resolveRoute.ts
index b3a6c018e7..eb711b95d2 100644
--- a/vike/shared/route/resolveRoute.ts
+++ b/vike/shared/route/resolveRoute.ts
@@ -1,7 +1,7 @@
 export { resolveRoute }
 
-import { assertUsage } from './utils.js'
-import { resolveRouteString } from './resolveRouteString.js'
+import { assertUsage } from './utils'
+import { resolveRouteString } from './resolveRouteString'
 import pc from '@brillout/picocolors'
 
 function resolveRoute(
diff --git a/vike/shared/route/resolveRouteFunction.ts b/vike/shared/route/resolveRouteFunction.ts
index f101834951..9daf592d02 100644
--- a/vike/shared/route/resolveRouteFunction.ts
+++ b/vike/shared/route/resolveRouteFunction.ts
@@ -3,8 +3,8 @@ export { assertRouteParams }
 export { assertSyncRouting }
 export { warnDeprecatedAllowKey }
 
-import { assertPageContextUrl, PageContextUrlInternal } from '../getPageContextUrlComputed.js'
-import { assert, assertUsage, assertWarning, hasProp, isPlainObject, isPromise } from './utils.js'
+import { assertPageContextUrl, PageContextUrlInternal } from '../getPageContextUrlComputed'
+import { assert, assertUsage, assertWarning, hasProp, isPlainObject, isPromise } from './utils'
 import pc from '@brillout/picocolors'
 
 async function resolveRouteFunction(
diff --git a/vike/shared/route/resolveRouteString.spec.ts b/vike/shared/route/resolveRouteString.spec.ts
index ee32d26c79..e50afe2b11 100644
--- a/vike/shared/route/resolveRouteString.spec.ts
+++ b/vike/shared/route/resolveRouteString.spec.ts
@@ -1,5 +1,5 @@
-import { resolveRouteString } from './resolveRouteString.js'
-import { stripAnsi } from '../../utils/stripAnsi.js'
+import { resolveRouteString } from './resolveRouteString'
+import { stripAnsi } from '../../utils/stripAnsi'
 import { expect, describe, it } from 'vitest'
 
 const r: typeof resolveRouteString = (a, b) => resolveRouteString(a, b)
diff --git a/vike/shared/route/resolveRouteString.ts b/vike/shared/route/resolveRouteString.ts
index 0a09485cc0..d3e58d83f8 100644
--- a/vike/shared/route/resolveRouteString.ts
+++ b/vike/shared/route/resolveRouteString.ts
@@ -5,8 +5,8 @@ export { analyzeRouteString }
 export { assertRouteString }
 export { getRouteStringParameterList }
 
-import { assertWarning, isBrowser, escapeRegex } from '../utils.js'
-import { assert, assertUsage } from './utils.js'
+import { assertWarning, isBrowser, escapeRegex } from '../utils'
+import { assert, assertUsage } from './utils'
 import pc from '@brillout/picocolors'
 
 const PARAM_TOKEN_NEW = '@'
diff --git a/vike/shared/route/resolveUrlPathname.ts b/vike/shared/route/resolveUrlPathname.ts
index 36e412e3cb..c14a93b5fe 100644
--- a/vike/shared/route/resolveUrlPathname.ts
+++ b/vike/shared/route/resolveUrlPathname.ts
@@ -1,7 +1,7 @@
 export { resolveUrlPathname }
 
-import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser.js'
-import { assert, assertUsage } from '../utils.js'
+import { assertIsNotBrowser } from '../../utils/assertIsNotBrowser'
+import { assert, assertUsage } from '../utils'
 assertIsNotBrowser() // Don't bloat the client
 
 type Part =
diff --git a/vike/shared/route/routing.ts b/vike/shared/route/routing.ts
index e1c827ed79..ded69a17a5 100644
--- a/vike/shared/route/routing.ts
+++ b/vike/shared/route/routing.ts
@@ -2,4 +2,4 @@
 //   import { resolveRoute } from 'vike/routing'
 // to:
 //   import { resolveRoute } from 'vike'
-export { resolveRoute } from './resolveRoute.js'
+export { resolveRoute } from './resolveRoute'
diff --git a/vike/shared/route/utils.ts b/vike/shared/route/utils.ts
index 0105f05d84..7e8fbc0e42 100644
--- a/vike/shared/route/utils.ts
+++ b/vike/shared/route/utils.ts
@@ -3,24 +3,24 @@
 //  - runtime of client (Client Routing)
 
 // Ensure we don't bloat runtime of Server Routing with the utils down below
-import { assertClientRouting } from '../../utils/assertRoutingType.js'
-import { isBrowser } from '../../utils/isBrowser.js'
+import { assertClientRouting } from '../../utils/assertRoutingType'
+import { isBrowser } from '../../utils/isBrowser'
 if (isBrowser()) {
   assertClientRouting()
 }
 
-export * from '../../utils/assert.js'
-export * from '../../utils/hasProp.js'
-export * from '../../utils/isObjectWithKeys.js'
-export * from '../../utils/sorter.js'
-export * from '../../utils/isPromise.js'
-export * from '../../utils/isPlainObject.js'
-export * from '../../utils/objectAssign.js'
-export * from '../../utils/slice.js'
-export * from '../../utils/unique.js'
-export * from '../../utils/isBrowser.js'
-export * from '../../utils/parseUrl.js'
-export * from '../../utils/checkType.js'
-export * from '../../utils/joinEnglish.js'
-export * from '../../utils/truncateString.js'
-export * from '../../utils/isCallable.js'
+export * from '../../utils/assert'
+export * from '../../utils/hasProp'
+export * from '../../utils/isObjectWithKeys'
+export * from '../../utils/sorter'
+export * from '../../utils/isPromise'
+export * from '../../utils/isPlainObject'
+export * from '../../utils/objectAssign'
+export * from '../../utils/slice'
+export * from '../../utils/unique'
+export * from '../../utils/isBrowser'
+export * from '../../utils/parseUrl'
+export * from '../../utils/checkType'
+export * from '../../utils/joinEnglish'
+export * from '../../utils/truncateString'
+export * from '../../utils/isCallable'
diff --git a/vike/shared/types.ts b/vike/shared/types.ts
index 0c642a6f24..e503ae7c06 100644
--- a/vike/shared/types.ts
+++ b/vike/shared/types.ts
@@ -14,11 +14,11 @@ export { PageContextBuiltInServer_deprecated as PageContextBuiltInServer }
 export { PageContextBuiltInClientWithClientRouting_deprecated as PageContextBuiltInClientWithClientRouting }
 export { PageContextBuiltInClientWithServerRouting_deprecated as PageContextBuiltInClientWithServerRouting }
 
-import type { PageContextUrlInternal, PageContextUrlClient, PageContextUrlServer } from './getPageContextUrlComputed.js'
-import type { ConfigEntries, ExportsAll, From, Source, Sources } from './getPageFiles/getExports.js'
-import type { Config } from './page-configs/Config.js'
-import type { PageContextConfig } from './page-configs/Config/PageContextConfig.js'
-import type { AbortStatusCode } from './route/abort.js'
+import type { PageContextUrlInternal, PageContextUrlClient, PageContextUrlServer } from './getPageContextUrlComputed'
+import type { ConfigEntries, ExportsAll, From, Source, Sources } from './getPageFiles/getExports'
+import type { Config } from './page-configs/Config'
+import type { PageContextConfig } from './page-configs/Config/PageContextConfig'
+import type { AbortStatusCode } from './route/abort'
 
 type PageContextServer<Data = unknown> = PageContextBuiltInServer<Data> & Vike.PageContext
 
diff --git a/vike/shared/utils.ts b/vike/shared/utils.ts
index 7f07cb2d2b..cc31f511bc 100644
--- a/vike/shared/utils.ts
+++ b/vike/shared/utils.ts
@@ -3,27 +3,27 @@
 //  - runtime of client (Server Routing)
 //  - runtime of client (Client Routing)
 
-export * from '../utils/assert.js'
-export * from '../utils/parseUrl.js'
-export * from '../utils/objectAssign.js'
-export * from '../utils/isCallable.js'
-export * from '../utils/isObject.js'
-export * from '../utils/unique.js'
-export * from '../utils/slice.js'
-export * from '../utils/sorter.js'
-export * from '../utils/isBrowser.js'
-export * from '../utils/hasProp.js'
-export * from '../utils/isPlainObject.js'
-export * from '../utils/compareString.js'
-export * from '../utils/isNotNullish.js'
-export * from '../utils/stringifyStringArray.js'
-export * from '../utils/filesystemPathHandling.js'
-export * from '../utils/cast.js'
-export * from '../utils/isPropertyGetter.js'
-export * from '../utils/isPromise.js'
-export * from '../utils/checkType.js'
-export * from '../utils/getValuePrintable.js'
-export * from '../utils/escapeRegex.js'
-export * from '../utils/isArray.js'
-export * from '../utils/changeEnumerable.js'
-export * from '../utils/objectDefineProperty.js'
+export * from '../utils/assert'
+export * from '../utils/parseUrl'
+export * from '../utils/objectAssign'
+export * from '../utils/isCallable'
+export * from '../utils/isObject'
+export * from '../utils/unique'
+export * from '../utils/slice'
+export * from '../utils/sorter'
+export * from '../utils/isBrowser'
+export * from '../utils/hasProp'
+export * from '../utils/isPlainObject'
+export * from '../utils/compareString'
+export * from '../utils/isNotNullish'
+export * from '../utils/stringifyStringArray'
+export * from '../utils/filesystemPathHandling'
+export * from '../utils/cast'
+export * from '../utils/isPropertyGetter'
+export * from '../utils/isPromise'
+export * from '../utils/checkType'
+export * from '../utils/getValuePrintable'
+export * from '../utils/escapeRegex'
+export * from '../utils/isArray'
+export * from '../utils/changeEnumerable'
+export * from '../utils/objectDefineProperty'
diff --git a/vike/tsconfig.json b/vike/tsconfig.json
index 8436f63b59..cb99402a36 100644
--- a/vike/tsconfig.json
+++ b/vike/tsconfig.json
@@ -1,14 +1,14 @@
 {
   "compilerOptions": {
     // Output
-    "target": "ES2020",
-    "module": "Node16",
+    "target": "ESNext",
+    "module": "ESNext",
     "outDir": "./dist/esm/", // ./dist/cjs/ is generated by ./tsconfig.cjs.json
     "rootDir": "./",
     "declaration": true,
     "noEmitOnError": false,
     // Resolution
-    "moduleResolution": "Node16",
+    "moduleResolution": "Bundler",
     "esModuleInterop": true,
     // Libs
     "lib": ["ES2021", "DOM", "DOM.Iterable"],
diff --git a/vike/types/defineConfig.ts b/vike/types/defineConfig.ts
index e0d148bb6b..ce8a236918 100644
--- a/vike/types/defineConfig.ts
+++ b/vike/types/defineConfig.ts
@@ -1,6 +1,6 @@
 export { defineConfig }
 
-import type { Config } from '../shared/page-configs/Config.js'
+import type { Config } from '../shared/page-configs/Config'
 
 function defineConfig(config: Config): Config {
   return config
diff --git a/vike/types/index-dreprecated.ts b/vike/types/index-dreprecated.ts
index 1619ba9eee..c8aac8f953 100644
--- a/vike/types/index-dreprecated.ts
+++ b/vike/types/index-dreprecated.ts
@@ -19,7 +19,7 @@ import type {
   Config as Config_,
   Env as Env_,
   ConfigEntries as ConfigEntries_
-} from './index.js'
+} from './index'
 
 /** @deprecated All types have been moved to `vike/types`.
  * Replace:
diff --git a/vike/types/index.ts b/vike/types/index.ts
index 9be3401d39..f7d2a715dd 100644
--- a/vike/types/index.ts
+++ b/vike/types/index.ts
@@ -1,14 +1,14 @@
-export type { PageContext } from '../shared/types.js'
-export type { PageContextServer } from '../shared/types.js'
-export type { PageContextClient } from '../shared/types.js'
-export type { PageContextWithServerRouting } from '../shared/types.js'
-export type { PageContextClientWithServerRouting } from '../shared/types.js'
+export type { PageContext } from '../shared/types'
+export type { PageContextServer } from '../shared/types'
+export type { PageContextClient } from '../shared/types'
+export type { PageContextWithServerRouting } from '../shared/types'
+export type { PageContextClientWithServerRouting } from '../shared/types'
 export type { ConfigVitePluginServerEntry } from '@brillout/vite-plugin-server-entry/plugin'
 
 // TODO/v1-release: remove these three exports
-export type { PageContextBuiltInServer } from '../shared/types.js'
-export type { PageContextBuiltInClientWithClientRouting } from '../shared/types.js'
-export type { PageContextBuiltInClientWithServerRouting } from '../shared/types.js'
+export type { PageContextBuiltInServer } from '../shared/types'
+export type { PageContextBuiltInClientWithClientRouting } from '../shared/types'
+export type { PageContextBuiltInClientWithServerRouting } from '../shared/types'
 
 export type {
   Config,
diff --git a/vike/utils/assert.ts b/vike/utils/assert.ts
index f35178fb3b..5072266441 100644
--- a/vike/utils/assert.ts
+++ b/vike/utils/assert.ts
@@ -9,11 +9,11 @@ export { overwriteAssertProductionLogger }
 export { isBug }
 export { setAlwaysShowStackTrace }
 
-import { assertSingleInstance_onAssertModuleLoad } from './assertSingleInstance.js'
-import { createErrorWithCleanStackTrace } from './createErrorWithCleanStackTrace.js'
-import { getGlobalObject } from './getGlobalObject.js'
-import { isObject } from './isObject.js'
-import { projectInfo } from './projectInfo.js'
+import { assertSingleInstance_onAssertModuleLoad } from './assertSingleInstance'
+import { createErrorWithCleanStackTrace } from './createErrorWithCleanStackTrace'
+import { getGlobalObject } from './getGlobalObject'
+import { isObject } from './isObject'
+import { projectInfo } from './projectInfo'
 import pc from '@brillout/picocolors'
 const globalObject = getGlobalObject<{
   alreadyLogged: Set<string>
diff --git a/vike/utils/assertIsBrowser.ts b/vike/utils/assertIsBrowser.ts
index 99562ff23f..5755ff227a 100644
--- a/vike/utils/assertIsBrowser.ts
+++ b/vike/utils/assertIsBrowser.ts
@@ -1,7 +1,7 @@
 export { assertIsBrowser }
 
-import { isBrowser } from './isBrowser.js'
-import { assert } from './assert.js'
+import { isBrowser } from './isBrowser'
+import { assert } from './assert'
 
 function assertIsBrowser() {
   assert(isBrowser())
diff --git a/vike/utils/assertIsNotBrowser.ts b/vike/utils/assertIsNotBrowser.ts
index bfd606dc65..013a099b76 100644
--- a/vike/utils/assertIsNotBrowser.ts
+++ b/vike/utils/assertIsNotBrowser.ts
@@ -1,7 +1,7 @@
 export { assertIsNotBrowser }
 
-import { isBrowser } from './isBrowser.js'
-import { assert } from './assert.js'
+import { isBrowser } from './isBrowser'
+import { assert } from './assert'
 
 /** Ensure we don't bloat the client-side */
 function assertIsNotBrowser() {
diff --git a/vike/utils/assertIsNotProductionRuntime.ts b/vike/utils/assertIsNotProductionRuntime.ts
index 6ece3e620e..8e52c8a85c 100644
--- a/vike/utils/assertIsNotProductionRuntime.ts
+++ b/vike/utils/assertIsNotProductionRuntime.ts
@@ -7,11 +7,11 @@ export { markEnvAsVikePluginLoaded }
 export { assertEnv }
 export { vikeVitePluginLoadedInProductionError }
 
-import { assert, assertUsage } from './assert.js'
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
-import { createDebugger } from './debug.js'
-import { getGlobalObject } from './getGlobalObject.js'
-import { isVitest } from './isVitest.js'
+import { assert, assertUsage } from './assert'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
+import { createDebugger } from './debug'
+import { getGlobalObject } from './getGlobalObject'
+import { isVitest } from './isVitest'
 assertIsNotBrowser()
 const debug = createDebugger('vike:setup')
 const vikeVitePluginLoadedInProductionError = `Loading Vike's Vite plugin (the vike/plugin module) is prohibited in production.`
diff --git a/vike/utils/assertKeys.ts b/vike/utils/assertKeys.ts
index aff4dd992c..f7a96b851a 100644
--- a/vike/utils/assertKeys.ts
+++ b/vike/utils/assertKeys.ts
@@ -1,8 +1,8 @@
 export { assertKeys }
 
 import pc from '@brillout/picocolors'
-import { assertUsage } from './assert.js'
-import { joinEnglish } from './joinEnglish.js'
+import { assertUsage } from './assert'
+import { joinEnglish } from './joinEnglish'
 
 function assertKeys<Keys extends readonly string[]>(
   obj: Record<string, unknown>,
diff --git a/vike/utils/assertNodeEnv.ts b/vike/utils/assertNodeEnv.ts
index ae9538b11d..3de176d611 100644
--- a/vike/utils/assertNodeEnv.ts
+++ b/vike/utils/assertNodeEnv.ts
@@ -20,9 +20,9 @@ export { handleNodeEnv_prerender }
 export { handleNodeEnv_vitePluginVercel }
 
 import pc from '@brillout/picocolors'
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
-import { assertWarning } from './assert.js'
-import { vikeVitePluginLoadedInProductionError } from './assertIsNotProductionRuntime.js'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
+import { assertWarning } from './assert'
+import { vikeVitePluginLoadedInProductionError } from './assertIsNotProductionRuntime'
 assertIsNotBrowser()
 
 function assertNodeEnv_build() {
diff --git a/vike/utils/assertNodeVersion.ts b/vike/utils/assertNodeVersion.ts
index bea325712d..c0dbd56d23 100644
--- a/vike/utils/assertNodeVersion.ts
+++ b/vike/utils/assertNodeVersion.ts
@@ -1,7 +1,7 @@
 export { assertNodeVersion }
 
-import { isNodeJS } from './isNodeJS.js'
-import { assertVersion } from './assertVersion.js'
+import { isNodeJS } from './isNodeJS'
+import { assertVersion } from './assertVersion'
 
 // node_modules/vike/package.json#engines.node isn't enough as users can ignore it
 function assertNodeVersion() {
diff --git a/vike/utils/assertRoutingType.ts b/vike/utils/assertRoutingType.ts
index 5b3cafda06..6f3f544307 100644
--- a/vike/utils/assertRoutingType.ts
+++ b/vike/utils/assertRoutingType.ts
@@ -2,9 +2,9 @@ export { assertClientRouting }
 export { assertServerRouting }
 export { checkIfClientRouting }
 
-import { assertUsage, assertWarning } from './assert.js'
-import { getGlobalObject } from './getGlobalObject.js'
-import { isBrowser } from './isBrowser.js'
+import { assertUsage, assertWarning } from './assert'
+import { getGlobalObject } from './getGlobalObject'
+import { isBrowser } from './isBrowser'
 import pc from '@brillout/picocolors'
 
 const state = getGlobalObject<{ isClientRouting?: boolean }>('utils/assertRouterType.ts', {})
diff --git a/vike/utils/assertSingleInstance.ts b/vike/utils/assertSingleInstance.ts
index da8d6b4f09..833c4327e6 100644
--- a/vike/utils/assertSingleInstance.ts
+++ b/vike/utils/assertSingleInstance.ts
@@ -6,12 +6,12 @@ export { assertSingleInstance_onAssertModuleLoad }
 //  - Show warning if entry of Client Routing and entry of Server Routing are both loaded
 //  - Show warning if vike is loaded twice
 
-import { unique } from './unique.js'
-import { getGlobalObject } from './getGlobalObject.js'
-import { projectInfo } from './projectInfo.js'
+import { unique } from './unique'
+import { getGlobalObject } from './getGlobalObject'
+import { projectInfo } from './projectInfo'
 import pc from '@brillout/picocolors'
 /* Use original assertUsage() & assertWarning() after all CJS is removed from node_modules/vike/dist/
-import { assertUsage, assertWarning } from './assert.js'
+import { assertUsage, assertWarning } from './assert'
 */
 const globalObject = getGlobalObject<{
   instances: string[]
diff --git a/vike/utils/assertVersion.ts b/vike/utils/assertVersion.ts
index 64c8623ae7..72b1ef8ae3 100644
--- a/vike/utils/assertVersion.ts
+++ b/vike/utils/assertVersion.ts
@@ -1,7 +1,7 @@
 export { assertVersion }
 export { isVersionOrAbove }
 
-import { assert, assertUsage } from './assert.js'
+import { assert, assertUsage } from './assert'
 
 function assertVersion(
   dependencyName: 'Vite' | 'Node.js',
diff --git a/vike/utils/augmentType.ts b/vike/utils/augmentType.ts
index c7e06059d8..3224abc4ec 100644
--- a/vike/utils/augmentType.ts
+++ b/vike/utils/augmentType.ts
@@ -1,6 +1,6 @@
 export { augmentType }
 
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 /** Help TypeScript augment the type of objects. */
 function augmentType<Thing, Clone>(thing: Thing, clone: Clone): asserts thing is Thing & Clone {
diff --git a/vike/utils/createErrorWithCleanStackTrace.ts b/vike/utils/createErrorWithCleanStackTrace.ts
index cfd8cfcdbb..da22dbc4f3 100644
--- a/vike/utils/createErrorWithCleanStackTrace.ts
+++ b/vike/utils/createErrorWithCleanStackTrace.ts
@@ -1,6 +1,6 @@
 export { createErrorWithCleanStackTrace }
 
-import { isNodeJS } from './isNodeJS.js'
+import { isNodeJS } from './isNodeJS'
 
 function createErrorWithCleanStackTrace(errorMessage: string, numberOfStackTraceLinesToRemove: number) {
   const err = new Error(errorMessage)
diff --git a/vike/utils/debug.ts b/vike/utils/debug.ts
index 9adddf380e..4cfaa1caa9 100644
--- a/vike/utils/debug.ts
+++ b/vike/utils/debug.ts
@@ -2,16 +2,16 @@ export { createDebugger }
 export { isDebugActivated }
 export type { Debug }
 
-import { isBrowser } from './isBrowser.js'
-import { isCallable } from './isCallable.js'
-import { objectAssign } from './objectAssign.js'
-import { assert, assertUsage } from './assert.js'
-import { checkType } from './checkType.js'
-import { getTerminalWidth } from './getTerminWidth.js'
+import { isBrowser } from './isBrowser'
+import { isCallable } from './isCallable'
+import { objectAssign } from './objectAssign'
+import { assert, assertUsage } from './assert'
+import { checkType } from './checkType'
+import { getTerminalWidth } from './getTerminWidth'
 import pc from '@brillout/picocolors'
-import { isArray } from './isArray.js'
+import { isArray } from './isArray'
 
-// Avoid this to be loaded in the browser. For isomorphic code: instead of `import { createDebugger } from './utils.js'`, use `globalThis.createDebugger()`.
+// Avoid this to be loaded in the browser. For isomorphic code: instead of `import { createDebugger } from './utils'`, use `globalThis.createDebugger()`.
 assert(!isBrowser())
 ;(globalThis as any).__brillout_debug_createDebugger = createDebugger
 
diff --git a/vike/utils/debugGlob.ts b/vike/utils/debugGlob.ts
index 84063440d2..f26546969b 100644
--- a/vike/utils/debugGlob.ts
+++ b/vike/utils/debugGlob.ts
@@ -1,3 +1,3 @@
-import { createDebugger } from './debug.js'
+import { createDebugger } from './debug'
 // TODO/v1-release: remove (or rename?)
 export const debugGlob = createDebugger('vike:glob')
diff --git a/vike/utils/filesystemPathHandling.ts b/vike/utils/filesystemPathHandling.ts
index c700b6c23d..64c5eb9335 100644
--- a/vike/utils/filesystemPathHandling.ts
+++ b/vike/utils/filesystemPathHandling.ts
@@ -1,7 +1,7 @@
 export { toPosixPath }
 export { assertPosixPath }
 
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 function toPosixPath(path: string): string {
   const pathPosix = path.split('\\').join('/')
diff --git a/vike/utils/findFile.ts b/vike/utils/findFile.ts
index 8f865beef3..c5adcfd5e7 100644
--- a/vike/utils/findFile.ts
+++ b/vike/utils/findFile.ts
@@ -2,8 +2,8 @@ export { findFile }
 
 import path from 'path'
 import fs from 'fs'
-import { isArray } from './isArray.js'
-import { assertPosixPath } from './filesystemPathHandling.js'
+import { isArray } from './isArray'
+import { assertPosixPath } from './filesystemPathHandling'
 
 type Filename = 'package.json' | 'vike.config.js' | 'vike.config.ts'
 
diff --git a/vike/utils/findPackageJson.ts b/vike/utils/findPackageJson.ts
index d175e426da..f2a688edf9 100644
--- a/vike/utils/findPackageJson.ts
+++ b/vike/utils/findPackageJson.ts
@@ -1,6 +1,6 @@
 export { findPackageJson }
 
-import { findFile } from './findFile.js'
+import { findFile } from './findFile'
 import { createRequire } from 'module'
 // @ts-ignore Shimmed by dist-cjs-fixup.js for CJS build.
 const importMetaUrl: string = import.meta.url
diff --git a/vike/utils/formatHintLog.ts b/vike/utils/formatHintLog.ts
index c80bb03275..a01aa485cd 100644
--- a/vike/utils/formatHintLog.ts
+++ b/vike/utils/formatHintLog.ts
@@ -1,5 +1,5 @@
-import { assert } from './assert.js'
-import { stripAnsi } from './stripAnsi.js'
+import { assert } from './assert'
+import { stripAnsi } from './stripAnsi'
 
 export { formatHintLog }
 
diff --git a/vike/utils/freezePartial.spec.ts b/vike/utils/freezePartial.spec.ts
index 9d993e32c2..edab805e45 100644
--- a/vike/utils/freezePartial.spec.ts
+++ b/vike/utils/freezePartial.spec.ts
@@ -1,5 +1,5 @@
 import { expect, describe, it } from 'vitest'
-import { freezePartial } from './freezePartial.js'
+import { freezePartial } from './freezePartial'
 import pc from '@brillout/picocolors'
 
 describe('freezePartial', () => {
diff --git a/vike/utils/freezePartial.ts b/vike/utils/freezePartial.ts
index 4d5f71e20e..bee6f061c8 100644
--- a/vike/utils/freezePartial.ts
+++ b/vike/utils/freezePartial.ts
@@ -3,7 +3,7 @@ export { freezePartial }
 import pc from '@brillout/picocolors'
 // Unit tests at ./freezePartial.spec.ts
 
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
 assertIsNotBrowser()
 
 function freezePartial(obj: Record<string, unknown>, allowList: Record<string, (val: unknown) => boolean>) {
diff --git a/vike/utils/getCurrentUrl.ts b/vike/utils/getCurrentUrl.ts
index 1efa798427..2768fc306b 100644
--- a/vike/utils/getCurrentUrl.ts
+++ b/vike/utils/getCurrentUrl.ts
@@ -1,7 +1,7 @@
 export { getCurrentUrl }
 
-import { parseUrl } from './parseUrl.js'
-import { assert } from './assert.js'
+import { parseUrl } from './parseUrl'
+import { assert } from './assert'
 
 function getCurrentUrl(options?: { withoutHash: true }): `/${string}` {
   const url = window.location.href
diff --git a/vike/utils/getFileExtension.ts b/vike/utils/getFileExtension.ts
index cd5e91b428..c353b5891b 100644
--- a/vike/utils/getFileExtension.ts
+++ b/vike/utils/getFileExtension.ts
@@ -1,6 +1,6 @@
 export { getFileExtension }
 
-import { slice } from './slice.js'
+import { slice } from './slice'
 
 function getFileExtension(id: string) {
   id = id.split('?')[0]!
diff --git a/vike/utils/getGlobalObject.ts b/vike/utils/getGlobalObject.ts
index d3f2faf130..f41649628b 100644
--- a/vike/utils/getGlobalObject.ts
+++ b/vike/utils/getGlobalObject.ts
@@ -1,8 +1,8 @@
 export { getGlobalObject }
 export { assertIsSingleModuleInstance }
 
-import { assert } from './assert.js'
-import { projectInfo } from './projectInfo.js'
+import { assert } from './assert'
+import { projectInfo } from './projectInfo'
 const projectKey = `_${projectInfo.projectName.toLowerCase()}` as const
 
 /** Share information across module instances. */
diff --git a/vike/utils/getMostSimilar.ts b/vike/utils/getMostSimilar.ts
index b8d3950b37..dddcf8a57c 100644
--- a/vike/utils/getMostSimilar.ts
+++ b/vike/utils/getMostSimilar.ts
@@ -1,8 +1,8 @@
 export { getMostSimilar }
 
-import { assert } from './assert.js'
-import { higherFirst } from './sorter.js'
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
+import { assert } from './assert'
+import { higherFirst } from './sorter'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
 
 assertIsNotBrowser()
 
diff --git a/vike/utils/getOutDirs.ts b/vike/utils/getOutDirs.ts
index 7536c9a2f0..2ac484549a 100644
--- a/vike/utils/getOutDirs.ts
+++ b/vike/utils/getOutDirs.ts
@@ -3,12 +3,12 @@ export { resolveOutDir }
 export type { OutDirs }
 
 import type { UserConfig, ResolvedConfig } from 'vite'
-import { viteIsSSR } from './viteIsSSR.js'
-import { assert, assertUsage } from './assert.js'
-import { pathJoin } from './path-shim.js'
-import { assertPosixPath, toPosixPath } from './filesystemPathHandling.js'
+import { viteIsSSR } from './viteIsSSR'
+import { assert, assertUsage } from './assert'
+import { pathJoin } from './path-shim'
+import { assertPosixPath, toPosixPath } from './filesystemPathHandling'
 import pc from '@brillout/picocolors'
-import { createDebugger } from './debug.js'
+import { createDebugger } from './debug'
 const debug = createDebugger('vike:outDir')
 
 type OutDirs = {
diff --git a/vike/utils/getRandomId.ts b/vike/utils/getRandomId.ts
index d9ce63beb5..00c350ff86 100644
--- a/vike/utils/getRandomId.ts
+++ b/vike/utils/getRandomId.ts
@@ -1,6 +1,6 @@
 export { getRandomId }
 
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 // https://stackoverflow.com/questions/1349404/generate-random-string-characters-in-javascript
 
diff --git a/vike/utils/getValuePrintable.spec.ts b/vike/utils/getValuePrintable.spec.ts
index 3d813f15fe..b4d3eda56c 100644
--- a/vike/utils/getValuePrintable.spec.ts
+++ b/vike/utils/getValuePrintable.spec.ts
@@ -1,5 +1,5 @@
 import { expect, describe, it } from 'vitest'
-import { getValuePrintable } from './getValuePrintable.js'
+import { getValuePrintable } from './getValuePrintable'
 
 describe('getValuePrintable()', () => {
   it('works', () => {
diff --git a/vike/utils/hasProp.ts b/vike/utils/hasProp.ts
index 8d93258190..518dd5c6bf 100644
--- a/vike/utils/hasProp.ts
+++ b/vike/utils/hasProp.ts
@@ -1,11 +1,11 @@
 export { hasProp }
 export type { ResolveTypeAsString }
 
-import { isCallable } from './isCallable.js'
-import { isObject } from './isObject.js'
-import { isArrayOfStrings } from './isArrayOfStrings.js'
-import { isObjectOfStrings } from './isObjectOfStrings.js'
-import { isArray } from './isArray.js'
+import { isCallable } from './isCallable'
+import { isObject } from './isObject'
+import { isArrayOfStrings } from './isArrayOfStrings'
+import { isObjectOfStrings } from './isObjectOfStrings'
+import { isArray } from './isArray'
 
 type TypeAsString =
   | 'object'
diff --git a/vike/utils/injectRollupInputs.ts b/vike/utils/injectRollupInputs.ts
index 50d07a6e85..c7858e10d2 100644
--- a/vike/utils/injectRollupInputs.ts
+++ b/vike/utils/injectRollupInputs.ts
@@ -2,9 +2,9 @@ export { injectRollupInputs }
 export { normalizeRollupInput }
 
 import type { ResolvedConfig, Rollup } from 'vite'
-import { assert } from './assert.js'
-import { isObject } from './isObject.js'
-import { isArray } from './isArray.js'
+import { assert } from './assert'
+import { isObject } from './isObject'
+import { isArray } from './isArray'
 type InputOption = Rollup.InputOption
 type InputsMap = Record<string, string>
 
diff --git a/vike/utils/isArrayOfStrings.ts b/vike/utils/isArrayOfStrings.ts
index 00c235badc..6a08a973af 100644
--- a/vike/utils/isArrayOfStrings.ts
+++ b/vike/utils/isArrayOfStrings.ts
@@ -1,6 +1,6 @@
 export { isArrayOfStrings }
 
-import { isArray } from './isArray.js'
+import { isArray } from './isArray'
 
 function isArrayOfStrings(val: unknown): val is string[] {
   return isArray(val) && val.every((v) => typeof v === 'string')
diff --git a/vike/utils/isDev.ts b/vike/utils/isDev.ts
index c3711365f5..8011c09b21 100644
--- a/vike/utils/isDev.ts
+++ b/vike/utils/isDev.ts
@@ -1,7 +1,7 @@
 export { isDev2 }
 export { isDev3 }
 
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 // We can propbably remove this file after we implement the Vike CLI
 
@@ -30,7 +30,7 @@ function isDev3(configEnv: ConfigEnv): boolean {
  * - https://github.com/vikejs/vike/issues/1791
  * - Calling Vite's createServer() is enough for hasViteDevServer to be true, even without actually adding Vite's development middleware to the server: https://github.com/vikejs/vike/issues/792#issuecomment-1516830759
  *
-import { getGlobalObject } from './getGlobalObject.js'
+import { getGlobalObject } from './getGlobalObject'
 const globalObject = getGlobalObject('utils/isDev.ts', { isDev: false, isDev_wasCalled: false })
 function isDev1(): boolean {
   globalObject.isDev_wasCalled = true
diff --git a/vike/utils/isFilePathAbsoluteFilesystem.ts b/vike/utils/isFilePathAbsoluteFilesystem.ts
index 8efe1ab1ad..bf00f3f675 100644
--- a/vike/utils/isFilePathAbsoluteFilesystem.ts
+++ b/vike/utils/isFilePathAbsoluteFilesystem.ts
@@ -2,8 +2,8 @@ export { assertFilePathAbsoluteFilesystem }
 export { isFilePathAbsolute }
 
 import path from 'path'
-import { assert } from './assert.js'
-import { assertPosixPath } from './filesystemPathHandling.js'
+import { assert } from './assert'
+import { assertPosixPath } from './filesystemPathHandling'
 
 /**
  * Asserts that `filePath` is an absolute file path starting from the filesystem root.
diff --git a/vike/utils/isHtml.spec.ts b/vike/utils/isHtml.spec.ts
index 0321d52fd5..5caf1df85b 100644
--- a/vike/utils/isHtml.spec.ts
+++ b/vike/utils/isHtml.spec.ts
@@ -1,5 +1,5 @@
 import { expect, describe, it } from 'vitest'
-import { isHtml } from './isHtml.js'
+import { isHtml } from './isHtml'
 
 describe('isHtml()', () => {
   it('works', () => {
diff --git a/vike/utils/isNpmPackage.spec.ts b/vike/utils/isNpmPackage.spec.ts
index 3be1efd99d..4fb6e92c0d 100644
--- a/vike/utils/isNpmPackage.spec.ts
+++ b/vike/utils/isNpmPackage.spec.ts
@@ -1,5 +1,5 @@
 import { expect, describe, it, assert } from 'vitest'
-import { isDistinguishable, isValidPathAlias, parse } from './isNpmPackage.js'
+import { isDistinguishable, isValidPathAlias, parse } from './isNpmPackage'
 
 describe('parse()', () => {
   it('basics', () => {
diff --git a/vike/utils/isNpmPackage.ts b/vike/utils/isNpmPackage.ts
index 41d7906eea..ef1c4ca6c0 100644
--- a/vike/utils/isNpmPackage.ts
+++ b/vike/utils/isNpmPackage.ts
@@ -12,8 +12,8 @@ export { getNpmPackageImportPath }
 export { parse }
 export { isDistinguishable }
 
-import { assert } from './assert.js'
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
+import { assert } from './assert'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
 assertIsNotBrowser()
 
 function isNpmPackageImport(str: string, { cannotBePathAlias }: { cannotBePathAlias: true }): boolean {
diff --git a/vike/utils/isObjectOfStrings.ts b/vike/utils/isObjectOfStrings.ts
index bd316f1aeb..fe58fc14dc 100644
--- a/vike/utils/isObjectOfStrings.ts
+++ b/vike/utils/isObjectOfStrings.ts
@@ -1,6 +1,6 @@
 export { isObjectOfStrings }
 
-import { isObject } from './isObject.js'
+import { isObject } from './isObject'
 
 function isObjectOfStrings(val: unknown): val is Record<string, string> {
   return isObject(val) && Object.values(val).every((v) => typeof v === 'string')
diff --git a/vike/utils/isObjectWithKeys.ts b/vike/utils/isObjectWithKeys.ts
index 512e0e9783..bb98d69ef4 100644
--- a/vike/utils/isObjectWithKeys.ts
+++ b/vike/utils/isObjectWithKeys.ts
@@ -1,4 +1,4 @@
-import { isPlainObject } from './isPlainObject.js'
+import { isPlainObject } from './isPlainObject'
 
 export { isObjectWithKeys }
 
diff --git a/vike/utils/isPromise.ts b/vike/utils/isPromise.ts
index 87b8ea6664..3551c2fd74 100644
--- a/vike/utils/isPromise.ts
+++ b/vike/utils/isPromise.ts
@@ -1,4 +1,4 @@
-import { isCallable } from './isCallable.js'
+import { isCallable } from './isCallable'
 export function isPromise(val: unknown): val is Promise<unknown> {
   return typeof val === 'object' && val !== null && 'then' in val && isCallable((val as Record<string, unknown>).then)
 }
diff --git a/vike/utils/isSameErrorMessage.ts b/vike/utils/isSameErrorMessage.ts
index 912c70b9b7..53be7014d9 100644
--- a/vike/utils/isSameErrorMessage.ts
+++ b/vike/utils/isSameErrorMessage.ts
@@ -1,4 +1,4 @@
-import { isObject } from './isObject.js'
+import { isObject } from './isObject'
 
 export { isSameErrorMessage }
 
diff --git a/vike/utils/isScriptFile.ts b/vike/utils/isScriptFile.ts
index 2ea551bbf8..186937a9a8 100644
--- a/vike/utils/isScriptFile.ts
+++ b/vike/utils/isScriptFile.ts
@@ -4,7 +4,7 @@ export { isTemplateFile }
 export { scriptFileExtensions }
 export { scriptFileExtensionList }
 
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 // We can't use a RegExp:
 //  - Needs to work with Micromatch: https://github.com/micromatch/micromatch because:
diff --git a/vike/utils/joinEnglish.ts b/vike/utils/joinEnglish.ts
index 559f6d41b2..5f6cd970d6 100644
--- a/vike/utils/joinEnglish.ts
+++ b/vike/utils/joinEnglish.ts
@@ -1,6 +1,6 @@
 export { joinEnglish }
 
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 // https://stackoverflow.com/questions/53879088/join-an-array-by-commas-and-and/53879103#53879103
 function joinEnglish(
diff --git a/vike/utils/normalizeHeaders.spec.ts b/vike/utils/normalizeHeaders.spec.ts
index dbb4c9ec06..167434fed7 100644
--- a/vike/utils/normalizeHeaders.spec.ts
+++ b/vike/utils/normalizeHeaders.spec.ts
@@ -1,5 +1,5 @@
 import { expect, describe, it } from 'vitest'
-import { normalizeHeaders } from './normalizeHeaders.js'
+import { normalizeHeaders } from './normalizeHeaders'
 
 describe('normalizeHeaders()', () => {
   it('works', () => {
diff --git a/vike/utils/normalizeHeaders.ts b/vike/utils/normalizeHeaders.ts
index 4fd744c4f7..b16f7a5ae0 100644
--- a/vike/utils/normalizeHeaders.ts
+++ b/vike/utils/normalizeHeaders.ts
@@ -1,6 +1,6 @@
 export { normalizeHeaders }
 
-import { isObject } from './isObject.js'
+import { isObject } from './isObject'
 
 function normalizeHeaders(
   /* This type is precise, too precise which can be annoying: e.g. cannot pass a string[][] argument because it doesn't match the more precise [string,string][] type.
diff --git a/vike/utils/objectAssign.ts b/vike/utils/objectAssign.ts
index 5e599773f4..ab860cbe75 100644
--- a/vike/utils/objectAssign.ts
+++ b/vike/utils/objectAssign.ts
@@ -1,6 +1,6 @@
 export { objectAssign }
 
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 // Same as Object.assign() but:
 //  - With type inference
diff --git a/vike/utils/parseUrl-extras.spec.ts b/vike/utils/parseUrl-extras.spec.ts
index 54233b6b59..fd4be6cc95 100644
--- a/vike/utils/parseUrl-extras.spec.ts
+++ b/vike/utils/parseUrl-extras.spec.ts
@@ -1,4 +1,4 @@
-import { normalizeUrlPathname, removeUrlOrigin, setUrlOrigin } from './parseUrl-extras.js'
+import { normalizeUrlPathname, removeUrlOrigin, setUrlOrigin } from './parseUrl-extras'
 import { expect, describe, it } from 'vitest'
 
 describe('normalizeUrlPathname()', () => {
diff --git a/vike/utils/parseUrl-extras.ts b/vike/utils/parseUrl-extras.ts
index 8caebc72ea..4b70295cc0 100644
--- a/vike/utils/parseUrl-extras.ts
+++ b/vike/utils/parseUrl-extras.ts
@@ -7,10 +7,10 @@ export { removeUrlOrigin }
 export { setUrlOrigin }
 export { getUrlPretty }
 
-import { assertUrlComponents, createUrlFromComponents, isBaseServer, parseUrl } from './parseUrl.js'
-import { assert } from './assert.js'
-import { slice } from './slice.js'
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
+import { assertUrlComponents, createUrlFromComponents, isBaseServer, parseUrl } from './parseUrl'
+import { assert } from './assert'
+import { slice } from './slice'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
 assertIsNotBrowser()
 
 function prependBase(url: string, baseServer: string): string {
diff --git a/vike/utils/parseUrl.spec.ts b/vike/utils/parseUrl.spec.ts
index 05b0f0e005..10fe89b239 100644
--- a/vike/utils/parseUrl.spec.ts
+++ b/vike/utils/parseUrl.spec.ts
@@ -1,4 +1,4 @@
-import { parseUrl } from './parseUrl.js'
+import { parseUrl } from './parseUrl'
 import { expect, describe, it } from 'vitest'
 import assert from 'assert'
 
diff --git a/vike/utils/parseUrl.ts b/vike/utils/parseUrl.ts
index 8571c08246..cf6318b0c5 100644
--- a/vike/utils/parseUrl.ts
+++ b/vike/utils/parseUrl.ts
@@ -18,8 +18,8 @@ export { createUrlFromComponents }
 export type { UrlPublic }
 export type { UrlPrivate }
 
-import { slice } from './slice.js'
-import { assert, assertUsage } from './assert.js'
+import { slice } from './slice'
+import { assert, assertUsage } from './assert'
 import pc from '@brillout/picocolors'
 
 type UrlPublic = {
diff --git a/vike/utils/path-shim.ts b/vike/utils/path-shim.ts
index e0aab9e38f..401eab43bb 100644
--- a/vike/utils/path-shim.ts
+++ b/vike/utils/path-shim.ts
@@ -3,7 +3,7 @@ export { pathJoin }
 // Simple shim for `import * from "node:path"` used by the server runtime.
 // Robust alternative: https://github.com/unjs/pathe
 
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 function pathJoin(path1: string, path2: string): string {
   assert(!path1.includes('\\'))
diff --git a/vike/utils/projectInfo.ts b/vike/utils/projectInfo.ts
index ccf50d4ab2..a7283a2c6c 100644
--- a/vike/utils/projectInfo.ts
+++ b/vike/utils/projectInfo.ts
@@ -1,4 +1,4 @@
-import { PROJECT_VERSION } from './PROJECT_VERSION.js'
+import { PROJECT_VERSION } from './PROJECT_VERSION'
 export const projectInfo = {
   projectName: 'Vike' as const,
   projectVersion: PROJECT_VERSION
diff --git a/vike/utils/requireResolve.ts b/vike/utils/requireResolve.ts
index a8e8ce748d..da7b85ad04 100644
--- a/vike/utils/requireResolve.ts
+++ b/vike/utils/requireResolve.ts
@@ -1,10 +1,10 @@
 export { requireResolve }
 
-import { assert } from './assert.js'
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
-import { assertIsNotProductionRuntime } from './assertIsNotProductionRuntime.js'
-import { assertPosixPath, toPosixPath } from './filesystemPathHandling.js'
-import { scriptFileExtensionList } from './isScriptFile.js'
+import { assert } from './assert'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
+import { assertIsNotProductionRuntime } from './assertIsNotProductionRuntime'
+import { assertPosixPath, toPosixPath } from './filesystemPathHandling'
+import { scriptFileExtensionList } from './isScriptFile'
 import { createRequire } from 'module'
 // @ts-ignore Shimmed by dist-cjs-fixup.js for CJS build.
 const importMetaUrl: string = import.meta.url
diff --git a/vike/utils/slice.ts b/vike/utils/slice.ts
index 4f54fec9b8..e7451aa7d7 100644
--- a/vike/utils/slice.ts
+++ b/vike/utils/slice.ts
@@ -1,4 +1,4 @@
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 export { slice }
 
diff --git a/vike/utils/sorter.ts b/vike/utils/sorter.ts
index b86056682d..b9a1ead9ab 100644
--- a/vike/utils/sorter.ts
+++ b/vike/utils/sorter.ts
@@ -1,4 +1,4 @@
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 export { higherFirst }
 export { lowerFirst }
diff --git a/vike/utils/stripAnsi.ts b/vike/utils/stripAnsi.ts
index 590410c704..c2a94dfa9c 100644
--- a/vike/utils/stripAnsi.ts
+++ b/vike/utils/stripAnsi.ts
@@ -1,6 +1,6 @@
 export { stripAnsi }
 
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
 assertIsNotBrowser()
 
 const ansiRegex = getAnsiRegex()
diff --git a/vike/utils/trackLogs.ts b/vike/utils/trackLogs.ts
index 509cc776f2..6d535f34f1 100644
--- a/vike/utils/trackLogs.ts
+++ b/vike/utils/trackLogs.ts
@@ -1,6 +1,6 @@
-import { isDebugActivated } from './debug.js'
+import { isDebugActivated } from './debug'
 import pc from '@brillout/picocolors'
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
 
 assertIsNotBrowser()
 
diff --git a/vike/utils/trimWithAnsi.spec.ts b/vike/utils/trimWithAnsi.spec.ts
index 432099e82a..d785642b00 100644
--- a/vike/utils/trimWithAnsi.spec.ts
+++ b/vike/utils/trimWithAnsi.spec.ts
@@ -1,4 +1,4 @@
-import { trimWithAnsi, trimWithAnsiTrailOnly } from './trimWithAnsi.js'
+import { trimWithAnsi, trimWithAnsiTrailOnly } from './trimWithAnsi'
 import { expect, describe, it } from 'vitest'
 import pc from '@brillout/picocolors'
 
diff --git a/vike/utils/trimWithAnsi.ts b/vike/utils/trimWithAnsi.ts
index 9b4cb4e6d1..f34e64c197 100644
--- a/vike/utils/trimWithAnsi.ts
+++ b/vike/utils/trimWithAnsi.ts
@@ -1,8 +1,8 @@
 export { trimWithAnsi }
 export { trimWithAnsiTrailOnly }
 
-import { assert } from './assert.js'
-import { stripAnsi } from './stripAnsi.js'
+import { assert } from './assert'
+import { stripAnsi } from './stripAnsi'
 
 const whitespaceRegex = /(\s+)/ // Capturing parathesis so that split preserves seperator
 
diff --git a/vike/utils/truncateString.ts b/vike/utils/truncateString.ts
index 364b60d862..42f26221e9 100644
--- a/vike/utils/truncateString.ts
+++ b/vike/utils/truncateString.ts
@@ -1,7 +1,7 @@
 export { truncateString }
 
 import pc from '@brillout/picocolors'
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 function truncateString(str: string, lenMax: number) {
   const lenMaxReal = lenMax - 3
diff --git a/vike/utils/urlToFile.ts b/vike/utils/urlToFile.ts
index e78d78a5ff..9b405b3c5f 100644
--- a/vike/utils/urlToFile.ts
+++ b/vike/utils/urlToFile.ts
@@ -1,9 +1,9 @@
 export { urlToFile }
 export { baseServer }
 
-import { assert } from './assert.js'
-import { parseUrl } from './parseUrl.js'
-import { slice } from './slice.js'
+import { assert } from './assert'
+import { parseUrl } from './parseUrl'
+import { slice } from './slice'
 
 // - When doing a `.pageContext.json` HTTP request, the base URL should be preserved. (The server-side will handle the base URL.)
 // - While pre-rendering there is no base URL
diff --git a/vike/utils/virtual-files.ts b/vike/utils/virtual-files.ts
index 258e8f78d0..1e350a978f 100644
--- a/vike/utils/virtual-files.ts
+++ b/vike/utils/virtual-files.ts
@@ -2,7 +2,7 @@ export { isVirtualFileId }
 export { getVirtualFileId }
 export { resolveVirtualFileId }
 
-import { assert } from './assert.js'
+import { assert } from './assert'
 
 const idBase = 'virtual:vike:'
 // https://vitejs.dev/guide/api-plugin.html#virtual-modules-convention
diff --git a/vike/utils/viteIsSSR.ts b/vike/utils/viteIsSSR.ts
index 41788858f3..5e6c799c48 100644
--- a/vike/utils/viteIsSSR.ts
+++ b/vike/utils/viteIsSSR.ts
@@ -1,5 +1,5 @@
-import { assert } from './assert.js'
-import { isObject } from './isObject.js'
+import { assert } from './assert'
+import { isObject } from './isObject'
 
 export { viteIsSSR }
 export { viteIsSSR_options }
diff --git a/vike/utils/warnIfErrorIsNotObject.ts b/vike/utils/warnIfErrorIsNotObject.ts
index 86c914f862..d3e0bf4593 100644
--- a/vike/utils/warnIfErrorIsNotObject.ts
+++ b/vike/utils/warnIfErrorIsNotObject.ts
@@ -1,8 +1,8 @@
 export { warnIfErrorIsNotObject }
 
-import { assertWarning } from './assert.js'
-import { assertIsNotBrowser } from './assertIsNotBrowser.js'
-import { isObject } from './isObject.js'
+import { assertWarning } from './assert'
+import { assertIsNotBrowser } from './assertIsNotBrowser'
+import { isObject } from './isObject'
 import pc from '@brillout/picocolors'
 
 assertIsNotBrowser()