/usr/lib/mailman/Mailman/Queue/ is in mailman 1:2.1.16-2.
This file is owned by root:list, with mode 0o755.
..
/usr/lib/mailman/Mailman/Queue/ArchRunner.py
/usr/lib/mailman/Mailman/Queue/BounceRunner.py
/usr/lib/mailman/Mailman/Queue/CommandRunner.py
/usr/lib/mailman/Mailman/Queue/IncomingRunner.py
/usr/lib/mailman/Mailman/Queue/MaildirRunner.py
/usr/lib/mailman/Mailman/Queue/NewsRunner.py
/usr/lib/mailman/Mailman/Queue/OutgoingRunner.py
/usr/lib/mailman/Mailman/Queue/RetryRunner.py
/usr/lib/mailman/Mailman/Queue/Runner.py
/usr/lib/mailman/Mailman/Queue/Switchboard.py
/usr/lib/mailman/Mailman/Queue/VirginRunner.py
/usr/lib/mailman/Mailman/Queue/__init__.py
/usr/lib/mailman/Mailman/Queue/sbcache.py