Out of curiosity, since I always wonder about ActivityPub integration between unlike apps: If a Git server used GitPub, could I comment on a PR from my Mastodon account?
It all depends on the vocabulary used. The Mastodon vocabulary is well defined already, but no vocabulary has been defined for GitPub for the time being.
Hopefully, GitPub will be the thinnest possible addition to ActivityPub, so that concepts (and vocabulary) are shared between GitPub and Mastodon, enabling comments between them.
