Feature request: git status --branch-only

Hello, I am working on a tol which should fetch changes from a remote repository on a user click. I want to limit fetch on the current remote tracking branch (something like "origin/master"), but surprisingly, it's hard to get it for all corner cases like a fresh clone of an empty repository or detached head, etc. E.g see this SO thread https://stackoverflow.com/questions/171550/find-out-which-remote-branch-a-local-branch-is-tracking/52896538

The most reliable way for me is to call

git status -b --no-ahead-behind --porcelain=v2

and parse the "# branch.upstream" line output. However, it is a bit slow on large repos and yields unused output for me. So, I propose a new switch "git status --branch-only" which would output branch status only.

Note: workaround is to specify some non-existing directory, like

git status -b --no-ahead-behind --porcelain=v2 .this-dir-does-not-exists

Thanks Ondra Medek