This is the most useful add-on I have ever used. It allows me to download rare piano sheet music + audio videos that are not available anywhere else. These are not copyright violations as they are mostly unpublished or published in Russia and other east European countries. And is it really reasonable to restrict downloads of movies that are 60 - 90 years old? YouTube is too grabby. Intellectual property rights have been taken way too far because of the extreme application of neoliberal capitalist ideology. I thank this developer from the bottom of my heart for this add-on. He is working hard on fixing YouTube's latest thwarting of this extension. Please continue to support them!