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.
That's unfortunate. Do you think it'll be worth the effort to port the LuLu base to Linux platform?