Thanks Barry for filing this. I was planning to do it but happy for you to beat me to it.

I had one question I'd been meaning to ask - with this change, can the code paths that were deprecated in 3.10 be removed in 3.11 (SelectableGroups and cast to dict of sequence of EntryPoint objects)? I was planning a slightly accelerated removal of the compatibility support because:

(a) The backport presented the deprecation for older Pythons already and so users will likely have migrated off the deprecated behaviors prior to the release of 3.10.
(b) It will be substantially harder to maintain the backport while the backport drops that support.
(c) In extreme cases, the backport is available to provide backward compatibility even for Python 3.11.

Let me know if you would rather I pose this question elsewhere or elaborate on the proposition. It doesn't affect the PR or move out of provisional.