A lot of this stuff is implemented in distlib and distil (distlib itself is just a library that provides the underpinnings, and some of the functionality required, such as actually installing stuff, is implemented in distil. I assume it's OK to add references to these? For example, distlib implements PEP 376, PEP 425, PEP 426, PEP 427, PEP 440, but only the last of these is mentioned on the PEP summaries page.

certainly mention the distlib implementations, but also let's be clear if there is a pypa-recommend tool that is user-facing (like pip), that is using those parts of distlib.

In most cases, that is not true currently.

As for mentioning distil, I'm inclined to say no. Up to this point, you've presented it as a proof of concept.

If you're wanting to mention "distil" as a real option for users, I'm concerned about fracturing the mind of users, but it's something to discuss I guess.

Marcus