There were several of these in the early/mid-2010s and all had different drawbacks that made them awkward to deal with. Offhand the only one I remember the name of was BugsEverywhere: https://github.com/aaiyer/bugseverywhere
Some issues I remember in general (not all of these applied to all these distributed bug trackers) that caused them to largely be abandoned:
* No single view of cases: At least one of them was tied to the current commit, so a case could be resolved on a branch but not master
* No central view for non-devs
* Updating happened outside normal git operations so it was easy to forget to push/pull case changes
* One of them that avoided the previous issue made heavy use of branches to keep its data in the main repo, so it turned the repo into a mess
* Even if you did push/pull, updates aren't synchronous with a central location so it was totally possible for two people to assign a case to themselves locally and not realize it until later
Task manager or bug tracker that resides right within git repository and can sync with GitHub.
It's on a very early stage of development, but somehow works. I'd really appreciate any ideas on what can be done/improved (actually, a lot).
https://github.com/jhspetersson/git-task