Mozilla Firefox – Official GitHub repo

I hope the bugzilla stay there even if only read only. There is a lot of historical data in there, especially for the web which was built as a "ad-hoc" platform, many times when you wonder why does X the answer can only be found in bugzilla (which will explain that some random website that used to be major but doesn't even exists anymore, did something for some browser that used to be major but doesn't even exists anymore).

Bugzilla was really good, and in retrospect decades ahead of its time. There is probably no self hosted bug tracker that comes close (or it there?)

Bugzilla is still the bug tracker for Firefox. I know if no plans to change that. (Github issues are not being used for the Firefox repo.)