Today I learned that one can disable the rather annoying WebRTC pop-up. In Firefox in about:config using the privacy.webrtc.legacyGlobalIndicator and setting it to false.

I came across this while using a website that would disable audio input as soon as the window lost focus, resulting in me being unable to use the page While a quick search on the internet only resulted in an unresolved Reddit thread suggesting a extensions, my own search in about:config was successful.