What's the meaning of "5" in global install paths like, pnpm/global/5/some-package?

[AlanSl]

With default settings, on PNPM 9, globally installed packages (on both my local Mac filesystem and an Alpine Linux Docker image) go into a directory named 5, for example: /Users/{me}/Library/pnpm/global/5/{package-name} or /usr/local/bin/global/5/{package-name}.

What's the significance of this magic number 5? Is it stable, does it depend on some other configuration somewhere?

If we've set ENV PNPM_HOME=/usr/local/bin in a Dockerfile, can we reliably expect to find globally installed files in /usr/local/bin/global/5 or does it depend on something?

I've tried looking in the docs and existing issues and could find anything, but I found several other issues where users were quoting global install file paths that included /global/5.

[AlanSl]

Looking at this discussion https://github.com/orgs/pnpm/discussions/3351 it looks like versions before pnpm@6 put their globally installed packages in a folder named for the major version number, then versions 6 and above just stuck with 5? So the 5 signifies that it was installed by a version that >=5.x?

Is this stable for future versions and is this documented anywhere?

[zkochan]

it will change only in a new major version of pnpm if the new major version makes breaking changes to the structure of the directory