@Brendanjones the Why and How sections of that issue are highly instructive.
Your understanding seems correct: In the most expansive version of this vision, anyone running an AP-enabled git instance (with one or more repos) can send MRs to another instance’s repo, without having to sign up there.
For starters this will be GitLab-specific, but that’s already huge for self-hosters of GitLab who currently don’t benefit from the internal interop of the GitLab.com network.
@Brendanjones also hugely impactful as a way around GitHub’s moat as the de-facto social network of open source development. I follow hundreds of developers on GitHub, though mainly just to keep track of who I’ve interacted with, effectively adding them to a dev-specific address book.
I have a much harder time keeping track of non-GitHub devs on alt platforms, but if I could follow them on the fediverse that’s actually preferable over GitHub’s proprietary follow list.