This add-on is UTTERLY USELESS UNTIL YOU PAY THEM. It puts a HUGE WATERMARK on the video in every video created by the 'UNLICENSED' version. If it would put a transparent unobtrusive watermark throughout the entire video or they put a smaller unobtrusive watermark, I would have no problem. But they put such a huge watermark that the video is become useless to watch. I today download a tutorial video from YouTube but this video downloader made it TOTALLY USELESS. If they mention this in the 'About this extension' section in this page, I might not add it in my browser but I would not report and write this review either. I don't know if this extension / developer violated Mozilla's Terms & Conditions but if I would in their review team, I would certainly remove it from the 'Extensions' page. In an era of 'FREE SOFTWARE' movement, THIS ADD-ON IS A BLACK SPOT ON THAT MOVEMENT AND ALSO ON MOZILLA ETHICS.