Carl Worth [off-list ref] writes:
Though actually I'd like it even more if there was some way to mark a
commit as having been "published" and the rebase strategy would refuse
to rebase published commits.
That is not "though actually", but an independent topic.
The need is indeed so real that there is a hook git-rebase pays
attention to in order to help you with that. I use it to
prevent myself from accidentally rebasing the topic branches
that I already merged to 'next'.
Unsurprisingly, it is called pre-rebase hook.