// https://www.ghacks.net/2019/06/18/block-autoplaying-video-and-audio-in-firefox-69-natively/
user_pref("media.autoplay.enabled", false);
// user_pref("media.autoplay.enabled", true);
user_pref("media.autoplay.default", 5);
user_pref("media.autoplay.enabled.user-gestures-needed", false);
user_pref("media.autoplay.allow-muted", false);
// media.autoplay.block-webaudio