This is a mirror that was being personally maintained, its been replaced by https://github.com/mozilla/gecko-dev, the maintainer sent an email saying the mirror was shutting down and people should move to the maintained version, this caused a bunch of traffic which caused github problems and they shut it down until they could fix it / bring it back up.

Dunno if its really news?

Seems like did a merge that somehow broke GitHub, and it's back to normal now.

(Don't forget, mozilla-central has more commits than GitHub can even count (they call it "10k+"), hundreds of forks, a few dozen commits a day, etc.. so it's atypical)

That's pretty standard for a private repo.

Only if you add a few zeroes. From the bug thread:

    This sounds like someone pushed the old shas into the new
    shas in some repo, which would be a ~1.5million commit push.

Misleading title a little - the repos were disabled due to file system issues.

(Assuming the title hasn't been changed…) Removed from service isn't the same as disabled? To my mind they're synonymous. But I suppose the former may sound a little more inflammatory.

Interestingly, the initial email reported the cause to be a ToS violation.

Well, my train of thought is that disabled means it won't work for whatever period of time while removed means it won't work ever again because it's gone.