The author is not subtle in letting know that this is intended to be open source replacement for Little Snitch (domain!).
But at-least macOS has little snitch, closest for Linux was opensnitch which was announced on HN few months back -
https://github.com/evilsocket/opensnitch/ but I'm not sure whether it's actively being developed though.
No sadly Opensnitch is dead.
Evilsocket for whatever reason went back to OSX and I (who was the other large contributor) did not feel the motivation to work on the project anymore.
But at-least macOS has little snitch, closest for Linux was opensnitch which was announced on HN few months back - https://github.com/evilsocket/opensnitch/ but I'm not sure whether it's actively being developed though.