how do I silence the alert noise that sounds each time Firefox reports actvity
When an alert box appears that contains info on trackers, cookies, suppression, mail, etc. an alert sound is played which can mean 50 alerts per hour.
Opaite Mbohovái (1)
Hi ! The default Firefox notification system doesn't notify you with audio, only visually.
So, my guess is that it's your OS that's being 'noisy' : https://www.imore.com/how-enable-and-disable-notification-sounds-your-mac
Also : http://osxdaily.com/2015/03/31/stop-messages-sound-effects-playing- mac-os-x/
Unless you happen to have this add-on installed and forgot all about it : https://addons.mozilla.org/en-US/firefox/addon/notification-sound/
Separate issue : Your system details show that your Flash needs to be updated :
Uninstall Flash for Mac OS : https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html
Downwload Flash for other systems : https://get.adobe.com/flashplayer/otherversions/