something about Forgejo/GitLab/GitHub I found out way too late: When you want to check out the code from a PR, you don't have to add a new remote, but can instead just pull the `refs/pull/<PR number>` git ref from the repo the PR was opened on.
@cyclopentane There's also the "reverse" in Forgejo, creating a pull request without a fork https://forgejo.org/docs/latest/user/agit-support/
AGit Workflow Usage | Forgejo – Beyond coding. We forge.