Oh you beautiful person, thank you so much for this. As a person who leaves too many YouTube tabs open and regularly gets an autoplay I can't find, this is my prayers answered.

Works

extremely useful for songs playing in the background, 10/10

works perfectly!

Many versions ago, firefox (i believe) copied chrome's useful speaker symbol to show which tab had audio.

At some point, Mozilla have decided, in their wisdom, that this useful feature is hidden, unless you actually hover over the tab in question.

I think i've found a workround but that requires making a .css file and configuring opacity.

This add-on literally detects active audio and moves active tab focus to the tab in question. Brilliant!

All because Mozilla somehow thought that hiding useful, visual info from a user would be beneficial 🤦‍‍♂️ Btw, i had a look in about:config and couldn't find any ability to control what visibility one has of audio activity

Awesome, simple lightweight extension. Click it, and it goes to the tab making noise. If you have multiple tabs making noise, clicking again will alternate to the next one.