On my system and firefox, no button appears. Has youtube made these kind of extensions 'impossible'? Btw. Firefox 108.0, Linux PopOS. I turned off all Adblockers and no-script extensions. The button is NOT emerging. So sadly I have to give it a 'one' star. I am still looking for an extensions that works. I also tried other mp3-downloader button-extensions, and never the button appears.