I see it mentions firejail which is a sandbox program. There may be something I need to allow in firejail, but I don't know what it's running.

I think this has something to do with Itch, not with Hidden Folks. I'm pretty sure that Unity, the game engine Hidde Folks was built with, does not need Firejail to run the game.

What is your question, anyway? ;)

No game should require root permission on Linux. I can't run it since it requires it to proceed and fails if I cancel.

I use firejail for security - it's a sandbox program as I mentioned - and new programs are run inside firejail by default. I can't see what program it's trying to run when the installer says firejail there so I don't know what changes to make to firejail to try to get it working. I don't have trouble with other games in Itch. So far this is the only game I've had this issue with.

If you could suggest which programs it might be trying to run/install I could try to whitelist or install them and see if the problem goes away.

I honestly have no idea why you're seeing that message, Tanath. This did not pop up in all the tests the QA company did when testing Hidden Folks on Linux. I can't find anything regarding Unity & Firejail on google, don't know what Firejail is, and I don't have a Linux computer or any knowledge of Linux to be of any help. If you can figure out what Unity wants from Firejail, I think that's your best bet in solving this issue.

I got the solution. I asked for help from the firejail people and it turns out that the Itch app uses firejail to sandbox games. The prompt is a one-time request coming from the Itch app, not the game.