Brilliant, well-maintained add-in! Dishita has managed to keep it working through many changes to YouTube.
I find it very useful for downloading exercise routines and music videos for playback offline.
I have contributed to its maintenance and urge other users to do likewise. A particular benefit of contributing is that I can download the audio tracks of music videos to listen to in the car or in the shower. I sing in a pop choir, and we often sing arrangements for which the publisher or other choirs have posted recordings online. It is a great help to listen to recordings of the arrangements we are singing.