Because we're not running postorius, and the moderate-by-mail change is not available in the older version of mailman3 we're running, I needed a tool to moderate lists from the command line. I found mailman-tools, but wasn't able to get them working with python3, so I started from scratch. Maybe someone else will find it useful

  https://git.tethera.net/mm3mod.git/about/

It's a work in progress, but I am running the version from that repo in production.

Like any program using the REST interface, in principle this has complete administrator access to your mailman site, so you need to to trust both this code and the users you let run it. I do run it in "kiosk mode" via ssh

   command="/home/listmod/.local/bin/mm3mod" ssh-rsa blahblah

in .ssh/authorized_keys. This is more of a keeping-honest-people-honest kind of thing.