It works, but it costs 18€ to get rid of an ugly watermark in the top right corner.
No word about that in the add-on description though. :(

I understand that developers want money for their work, but then say it upfront.
There's a lack of transparacy going on here.

You also need to download a companion app, by the way (kind of a video codec?) or it won't work.

Was great on Ubuntu, even worked on sites with tricky JavaScript-enabled videos like saddleback.com, but now (probably due to the new snap-based Firefox on Ubuntu) just says I need to install the companion app (which is already installed). Unfortunately, going to the support link here or on the plugin's home page just takes you to a Google Groups page that displays "Banned content warning". Not sure if this is Big Tech trying to squash a tool to download from YouTube or what, but it means the plug isn't useful on Ubuntu any more. :(

This extension meets most challenges where others may falter

sometimes it doesn't download. very inconvenient.

Good extension but the user interface is just... terrible... so hard to find the file and format you want to save to, instead you get coloured icons (as submenus? options? different lists?) that you don't know what they are good for. Crazy.

es war das beste aber jetzt nicht mehr wir mussen noch dazu diese app
Video DownloadHelper Companion App 1.6.3

I'm registered and getting a QR anyway!???

Kept a pre-Quantum version of Firefox along with a previous version of Video Download Helper on a flash drive. This older version gets 5 stars and is excellent.
Sadly, the current version is much less powerful and needs a paid "Companion add-on" to work for many sites. No thanks.
Having to fire up the older version to download around 40% of the videos I want.

THIS IS THE BEST DOWNLOADER I HAVE HAD, EASY TO USE AND EFFICIENT.

The plug-in have memory leak issue when watching live video, using a lot of memory and CPU usage.