We have the motd Gerrit plugin installed. That was done back in 2018 as a potential way to inform people having trouble to fetch when a branch got removed: T190810. We never used the feature and should remove it.
- remove motd from the the wmf/stable-* branches
- remove etc/motd.config from the deploy/wmf/stable-* branches
- remove the Puppet managed symlink from $GERRIT_SITE/etc/motd.config to the deployed file
- ensure both plugins/motd.jar and etc/motd.config are gone after deployment