Support multiple versions and languages of documentation

Is there guidance or documentation somewhere how I can support API and conceptual documentation for multiple versions of the same library? I am looking for a behaviour that is similar to docs.microsoft.com where you can select the the version of .NET for an API or conceptual article.

Also docs.microsoft.com has multi-language support (e.g. docs.microsoft.com/de-de/). How could I use docfx to add a similar support for multiple languages?

Start by reviewing DocFX's existing documentation and the discussion on this issue, then compare the requested behavior with docs.microsoft.com's version selector and locale paths. Done would be clear guidance or documented support for versioned API and conceptual documentation and multiple languages.

Written by the indexing model from the issue text.