I have cut the branch and it failed, I then tried again but since the VisualEditor submodule got fetched out I got:
Cloning into '/tmp/make-wmf-branch/VisualEditor/lib/ve'... Submodule path 'lib/ve': checked out '7420443fe551e44ae4180c8b14b542d7e8ed9de1' cd lib/ve 'git' 'checkout' '-q' '-b' 'wmf/1.32.0-wmf.22' 'git' 'push' 'origin' 'wmf/1.32.0-wmf.22' Permission denied (publickey). fatal: Could not read from remote repository.
The script should not attempt to make a branch for an extension submodule.