It's Dead!
Used to be a great extension but the webpage is dead, extension is also dead because it used the webpage.
Don't bother anymore!

actually a redirect for 4k download apps

adds a button to the upper right section of firefox not youtube and runs in the back ground constantly but does nothing when clicked on and won't download MP3s

Will download eines Programms :(((

clicked on download link on YT video, took me to a different website (4K Download). Nope. Removed.

es bueno

Najlepszy konwerter filmów z yt, szkoda że nie działa :C nigdy cię nie zapomnę simple youtube converter, byłeś dobrym kompanem przy zgrywaniu filmów T>>T

funktioniert seit einiger Zeit nicht mehr, Konvertierungsserver scheint defekt zu sein, zeigt nur Debian-Standardwelcome.

Jelenleg nem működik!

I can't use it anymore. I keep getting the error "error in server response ... ". I've been getting that error for quite some time now. I don't think this add-on works anymore and doesn't look like this will be updated either. I do hope I am wrong on that though.