This used to be the best add-on for downloading any video from youtube. It took a while to download, but there was nothing wrong with the video in the end, and it had no watermark or QR code or the like. But for months now it has not worked. At best, it will download the audio and video files, but it will not combine the two to give you the video you wanted to download from youtube. In short, this add-on does absolutely nothing now.