From the Cambridge EEG zulip:
15:25 Jon Ludlam
When you push to a forked tangled repo, and on the terminal it says 'create a PR at this link' - be warned, by default it'll create a PR to your own repo, not the repo it's forked from, unlike github!
the compare URL emitted offers a comparison between the new ref and the default ref on the same repo, but if the repo is a fork, we probably want to compare new ref to the default ref on the fork!
thanks @jon.recoil.org for the report.
potential fix:
unlike github, where forks utilize the same bare git repository, we need to prefill the user + repository pair to identify the upstream repository.