It does not work.

Anyway I would never install it in my main browser, because its code is secret and it can see all my passwords and other things that I write.

See:

https://support.mozilla.org/en-US/kb/permission-request-messages-firefox-extensions#w_access-your-data-for-all-websites

"The extension can read the content of any web page you visit as well as data you enter into those web pages, such as usernames and passwords."

This extension will place a donate button on every YouTube page that just says "Donate". The donate button leads to an obscure patreon page. I thought my computer was infected with malware.

Trash, is a front for a separate converter that throttles down to uselessness after 3 conversions.

Used to be good. Not anymore

"now it wants you to install malware"
screenshot:
http://ipic.su/img/img7/fs/YouTubevideoconvertertoMP3.1567194881.png

last update killed it - now it wants you to install malware

Doesn't work. All I get is "Status: Error - Contains Copyrighted Material" :( :(

broken, complicated

8-18-20- Doesn't work: "The SSL certificate presented by the server did not pass validation. This could indicate an expired SSL certificate or a certificate that does not include the requested domain name." There being no way to report an issue, I'm left with a review. Wish they had a simple "report trouble" button!