Those script names would already have code to handle name changes based on existing abiflags/soabi string (as FreeBSD does), and would be trivial to modify for 'm' removal.

For third party stuff: we use setuptools --record for 'everything', so as long as filenames are 'correct' for the files that are actually installed, and downstreams are clear what the scope of the changes are, 'm' removal is not an issue when it come so packaging third party packages/extensions.

A new file extension format or substantially more complex magic would be, on the other hand.

A new minor is a good time to make these changes, and there's nothing really blocking about a new python38 port/package, and nothing consumes it yet in downstream OS's