You can set "upstream" to another local branch, no remote is required, it's just how it's typically used. Under the hood it's just a way of naming another refer

You can set "upstream" to another local branch, no remote is required, it's just how it's typically used. Under the hood it's just a way of naming another reference as a divergence point. I use this extensively with Git(Hub|Lab) (PR|MR)'s. I set the upstream to "master" but push to "topic". The "push.default" docs cover how to have your cake and eat it too there.