the author got greedy...no longer able to download mp3 unless u donate

This is a switch bait scheme. You won't be able to download in proper HD formats unless you cough up some cash first. They explain how you "need powerful server infrastructure" to actually download in HD and how it's "limited to PRO users only". There are literally TONS of other Firefox addons that do the same job better, and for free. My suggestion to the developers is to find a real job. Makes you wonder why Mozilla is recommending this addon.

Does not work at all.

devi diventare PRO per potere scaricare un MP3

Сначала платите, потом скачивайте. Удалил.
Pay first, then download. Deleted.

doesn't work, you need to pay, lol yeah right. there are better websites to download from anyways, and in higher quality. 0/10

Doesnt work as advertised, 360p only.

This junk extension doesn't deliver 80% of what it promises unless you buy a pro package

MP3 option does not work.

Gave a $15 donation after joining because I was getting 1040p downloads. A few weeks later I could not even download 780p with the following message that I need "pro":
Youtube switched to separate audio/video streaming technology for higher quality formats and no longer provides direct 720p (Since 24 September 2018)/1080p/mp3 streams. Converting these streams to downloadable formats for you needs powerful server infrastructure, therefore 1080p/mp3 downloading has been limited to PRO users. Read more at - https://videodroid.org/pro_upgrade.html. FREE users can download all formats in CACHE where some PRO users fetched the video/audio in past 24 hours, to test the feature you can try downloading popular videos.

сразу просят деньги

This app does not support HD downloads, only 720p. For HD, you need to pay for the premium version of this app.

Shit addon, just there to grab your money. If you want anything better than potato, this is not the addon for you. I'd wager most of the reviews and installs are faked

Funktioniert nicht. Bei Benutzung wird man aufgefordert, eine Pro-Version zu kaufen.