At one point in time (prior to 1.2), VyOS firewall had p2p filtering based on application rules. That has been removed a long time ago, but the code is still in the firewall_rules module.

The code and the corresponding documentation and configuration should be removed. It will technically be a "breaking" change, since the configuration will change; however it would not work on any supported version for Ansible, so it is a bug fix.