git-webkit does a good job handling commits made on `main` and then converted to PRs, but if a commit is made on a branch managed by an alternate remote, it won't be able to determine the remote from the branch point. In general, this is actually a somewhat difficult problem because the same branch may be owned by multiple remotes in various states of up-to-dateness. We want to make a PR agains the most up-to-date of the remotes which are tracking the branch we madde a commit on.