After 'git webkit pr' creates the PR, it should comment on Bugzilla bug with PR number (currently it doesn't). This is assuming git-webkit knows the bug number (either from user input or commit message). If not, it can ask for the bug number.
Although, I am not sure yet if we want to enforce having a Bugzilla bug for every PR.
Resolved this in https://bugs.webkit.org/show_bug.cgi?id=236339.
*** This bug has been marked as a duplicate of bug 236339 ***