Version 9.4.0-3 of python-keystonemiddleware is marked for autoremoval from testing on Fri 10 Jun 2022. It depends (transitively) on qpid-proton, affected by #1006562. You should try to prevent the removal by fixing these RC bugs.
vcswatch reports that
this package has been uploaded into the archive but the debian/changelog in the
VCS is still UNRELEASED. You should consider pushing the missing commits
or updating the VCS.