Documentation for bio.tools and related projects are maintained in GitHub:
https://github.com/bio-tools/biotoolsDocs
Documentation files are written in reStructuredText and have the file extension .rst. Uploading a file to GitHub will trigger a rebuild of the docs. GitHub include the file index.rst which defines the menu structure. Each menu item corresponds to a GitHub file, which (by convention) should have the same name as the menu item: use concise names!