There is a widely reported problem with the add-on not detecting YouTube video correctly. Judging from the reviews, that hasn't been fixed yet (the last update was January 6th, so the developer hasn't gotten any updates through the approval process yet since this started). * Reviews: https://addons.mozilla.org/firefox/addon/video-downloadhelper/reviews/ * Developer's Help page: https://github.com/aclap-dev/video-downloadhelper/discussions Last time I checked (January 22nd), there was a post on the forum mentioning the option of testing a beta version of the add-on. The discussion starts around here: https://github.com/aclap-dev/video-downloadhelper/discussions/1074#discussioncomment-11914403 Note: I have not installed or tested this myself, and there probably are other new threads since then.