The current state of things

Right now the extension is looking for the bridge under /opt/fx_cast/ but inside a snap, Firefox is unable to read such directory.

A possible approach

Under Linux, when /opt/fx_cast/bridge fails to be found, could it be possible to look for the bridge under a user-owned directory (like $HOME, for example)? Maybe a symlink could make the trick in such case.

Another possible approach

Give the user the option to indicate the path under which the bridge is located.

Note

I'm not by any means a Linux nor a Firefox extensions expert. But I'd like to try fx_cast without giving away the option of using Firefox as a snap (I like it to has limited access to my system).