There is one open PR on GitHub which was not accepted into to official repository. I would like to merge this PR into my fork. It seems the forked repository which the PR was made from was deleted meanwhile. I am able to get the complete change data from the PR as a patch file, but there is one information I am missing so that I can apply it: which commit should the patch apply to? I was trying various points in the repository history, but there were always a few "hunks" which could not be applied.
The PR I am talking about is Flying Saucer PR #22, the patch file can be obtained by appending .patch to the URL (thanks Download Github pull request as unified diff to describing this).
Is there a way to get the commit hash or some other identification of the point in the target repository history against which the PR was made, or some other way to merge such inactive and abandoned PR into my own fork?