Whenever you’re using the micrphone or the webcam in Mozilla Firefox, it displays a little widget at the top of your display. This little widget can be annoying. Here’s how to get rid of it:
toolkit.legacyUserProfileCustomizations.stylesheets
~/.mozilla/firefox/your-profile-folder/chrome/userChrome.css
(create it if
it doesn’t exist):
/* Add the following line at the top of the file if it doesn't already exist. */
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
#webrtcIndicator {
display: none;
}