I had an existing branch for a PR for https://bugs.webkit.org/show_bug.cgi?id=244134, but had not pushed a PR yet (because of the issue in https://github.com/WebKit/WebKit/pull/3580). When on that branch, I did `git webkit pr --no-update`, and it tried to push the PR to https://github.com/WebKit/WebKit/pull/3482. I expected it to make a new PR.
Then I got stuck on my local PR branch, unable to specify a new bug to push to. I then deleted this branch with `git branch -D` but I still get: OpenSource % git webkit pr --issue 244285 'eng/REGRESSION253549main--iOS--2X-animationsLayout-tests-are-constant-failures' already exists Abandoning pushing pull-request because 'eng/REGRESSION253549main--iOS--2X-animationsLayout-tests-are-constant-failures' could not be created
<rdar://problem/99065079>
This is either fixed by https://bugs.webkit.org/show_bug.cgi?id=244660 or not-to-be-fixed. Ultimately, GitHub uses branch names as the primary identifier for PRs. We can use state and author to further differentiate, but beyond that, branch names are the primary PR identifier.