I wish this point was stressed more often. Git, to which we've switched reasonably recently after some pain, accommodates many many workflows. We should embrace that!!

E.g. if browser living people want to make PRs to an intermediate repo on GitHub, they can today! And then once they're reasonably stable and agreed upon, some email wizard (really, can be me, even though I'm not really a wizard) can push them to main repo, and even adjust a commit message or two. Git provides lots of commands for that,. I'm happy to explain and document them, though I doubt I'm the only such expert here.

The main question is where the discussion happens: it has to be email, period. And right now it's debbugs and emacs-devel. And yes I know that GitHub/gitlab do pretty links automatically between web UI parts, but how is that so different from sending email where you say you have a public branch with x commits here or there?

My two cents,

João