They're too busy spamming their anti-tracker and "anti-virus" to make the downloader work.
Useless.

Doesn't work.

No funciona. It does not work

It used to work perfectly. Not anymore.

doesn't work at all with dailymotion videos. But sure is able to show you a bunch of other ads.

使い物にならない。

Bullshitters - Their website claims the add-on is necessary, but it doesn't return the video, just a bunch of advertisements. This Add-on is basically ad bait.

Not intuitive at all. No useful instructions, no indication how to download to your hard drive. You see a string of unlabeled icons and then get a progress bar that says 100%, but there's nothing telling you what to do next or how to save the file you apparently just loaded... somewhere. A ten-second video, or even 2-3 screenshots, would have fixed this.