Borderliner you can request a package, instructions are in the help center.
I don't see this needing to be included with Plasma desktop. ufw or firewalld are required dependencies for plasma-firewall and neither are currently installed by default on Solus. Should the dev team decide to include one of those options as base package on new installs, maybe this could be included then? I would request the pacakge be added to the repos so that users who have chosen to install ufw or firewalld on Plasma can also install this if they'd like.
