Git itself is already capable of distributed usage, which is better than federated/decentralized.
'Distributed' and 'decentralized' in this sense:
But in terms of the Git hosting service, with an issue board and all that, which is often called a "git forge", you've got Forgejo working on an implementation, as well as ForgeFed as a general protocol (also work-in-progress).
It's funny how git was carefully designed to be decentralized and resistant to failure from any single node... and we immediately put all our fault tolerance on the back of one corporate-owned entity. Welp.
GitHub like services, no. Codeberg/forgejo looks promising, but theres a lot of discussion on what it should "look" like. Seems like its a pretty big challenge to do correctly.
Wouldn't help if your chosen instance is down, same problem unless multiple other people are storing your code on their servers
Otherwise it kinda already is federated, you can have multiple remotes configured for a repo and push to both at once I'm pretty sure, then if one goes down you just use the other and sync later
I mean, it's decentralized alright, but it doesn't mean it's HA or automatically replicated. You can just use a different origin server and push/pull from it instead.
My comment is more about how we have this decentralised tool, but we're unable to get our collective heads out of the centralised model. We e ended up turning it back into centralised VCS.