I am using Parabola (based on Arch) and I would like to use firejail to sandbox one or two less trusted applications (steam, in particular). However, when running applications in firejail (even with the --noprofile option, which is supposed to give the least-restrictive sandbox), I don't hear any sound. I have tried with steam and rhythmbox and have the same problem with both.
I have an open ticket here on github. I am using pulseaudio and I suspect the issue may be similar as to why I also get no sound when I run the same applications from the terminal as the root user (because firejail itself needs superuser priviledges to setup the sandbox, before handing over to the jailed application).
Is there a way I can enable sound in pulseaudio for the root user, such that if I log in to the desktop as a regular user;
su to root in the terminal; and then run rhythmbox, the sound will play? I am aware of this existing answer; however, it doesn't seem to work for me (presumably, this would only work if I were to log in to the entire desktop session as root, which I don't want to do).