I am at Google, but that's probably not relevant since the reason I was curious about this is that my personal website currently implements a git server over HTTPS[1], and git's CLI/API for that is not the friendliest[2]. It sounds like jj hasn't reached the point of tackling this problem space yet, which is okay. Thanks for confirming I wasn't missing out on something.
[1] https://pkg.go.dev/github.com/shurcooL/home/internal/code#Ne...
[2] https://pkg.go.dev/github.com/shurcooL/home/cmd/githook/pre-...