https://github.com/evilsocket/opensnitch

its an application based firewall, something i sure miss from my windows days (outpost) - and something im sure users coming from windows would appreciate.
for example id like to be able to block the proprietary nvidia drivers from calling home, i suspect it does, and many other things.
its port of the Little Snitch firewall application for MacOS

there are no application firewalls in solus repos (that i know of)

GPL 3

no versioned source tarball/zipfile :/

a little more info https://www.linuxuprising.com/2018/04/how-to-install-opensnitch-application.html