This used to be a useful extension but, following Firefox changes, they introduced a companion app. That was ok for a while but now they are just trying to make money. For the last few weeks, the companion app hides downloads that the free add-on would normally show (and other download apps still show) to try and force you to then pay to remove the watermark it adds to the download (that shouldn't need the companion app at all). I proved this by uninstalling the companion app, re-starting Firefox and then the free add-in showed all the video formats again. Problems with the video? No, I ran the test it on VDH's own advertising video on YouTube! The companion app is now hijackware just to try and make money.