Git is a content-addressable filesystem with a VCS interface on top of it. jj needs a content-addressable filesystem for a backend, and currently only uses git'

Git is a content-addressable filesystem with a VCS interface on top of it. jj needs a content-addressable filesystem for a backend, and currently only uses git's implementation in released versions, but the devs are working on their own to serve as a "native" backend. At least in theory, just about any content-addressable filesystem could be used, e.g. IPFS, though many would not be efficient.