Greasy Fork is available in English.
Adds a MP3 Download button next to the subscribe button, thanks to youtubeinmp3 for their simple download service (http://youtubeinmp3.com/api/). Based off magnus's youtube2mp3 code. Just used something different as it wont open another tab.
Quality and Clip length
This script works.
Too bad the service this script are using, creates a lower conversion quality. And has a bottleneck, it can't convert longer clip than 110 minutes.
Other than that it's a great and fast script. Good Work.
For those who want higher quality and convert longer clips. Try mine: https://greasyfork.org/scripts/1931-youtube2mp3