It's not just used by docker/packman. But also e.g. by the chrome sandbox used by e.g. electron apps (or e.g. 1password). Through that sandbox helper binary c

It's not just used by docker/packman. But also e.g. by the chrome sandbox used by e.g. electron apps (or e.g. 1password). Through that sandbox helper binary can also work with being a suid program. I also wouldn't be too surprised if e.g. proton will start using user namspaces at some point in the future. So for any non-hardened desktop linux system you probably should _not_ disable it! (For many servers or special hardened Linux it often isn't a bad idea to disable it.)