I've been trying the SimpleFirewall extension for sometime...
Once I get it to working, then I need to modify the System extension to something more.
In the process, I see that sometime the systemextension in /Library/SystemExtension does not get refresh.
WWDC 2019 doc on this says, if we erase the Firewall.app from /Applications folder, it does cleans up correctly. Even though there is no running extension for this package, it SAYS IT DID ERASE, THE FOLDER DOES NOT GET CLEANED.
Sometime it cleans correctly so there are some time when sticky stuff still around ( reboot or complete shutdown restart does not help).
Essentially very instable enviroment....
We can do the sudo rm -rf --- But still it does not know how to bring the Extension to that folder and starts the Firewall app.... Spins...
Thanks,
Prokash