Keybase, outside of the distributed bit along with the question of their future, provides zero-knowledge git repositories (they’ve literally got no idea what is in your repositories, including metadata).
https://github.com/forgefed/forgefed is a github alike that is federated via ActivityPub. this distributes content to a bunch of servers, but it is not cryptographic, not meant to be censorship-resistant. i think this could be layered in to ActivityPub, particularly by making use of Signed HTTP Exchanges to verify content origin, & then you'd still need a way to find alive hosts.