Elsewhere on this page, the developer has announced this extension is discontinued:

"Sorry to announce but Ant Video downloader is discontinued and will no longer be updated. Support is closed."

It requires you to install a shady desktop program for it to work. What's the point of installing a web extension then...

I give it 5 stars because I tried it against another download app with the same features but the latter did not give me a very good result. I see that in both apps, the video is downloaded in segments, but in the latter the contrast between audio and video is very noticeable. On the other hand, in this one it gives a better result, but even so there is a small cut in the image at certain moments of the video. I have downloaded a 20-minute video in both apps, this one has a better performance but visualizing the result, I still think it needs to be fine-tuned a bit more.

Das Addon funktioniert nicht mehr und lädt auch keine Videos mehr herunter.

Useless, You Tube/Google no longer alows downloading, even where it's perfectly legal, under jurisdiction.

Best downloader ever ♥

It works but a step by step tutorial on how to use it is completely needed. Even on the Ant Video Downloader official website they can do a good tutorial (a detailed one) they should do one.
How to use it?: You have to use Firefox (won't work on Librewolf), install the AVD native app on windows and then install the addon Ant Video Downloader on Firefox. Then go to settings of the addon and allow sending data to the native app cookies on privacy settings. After all that, open or refresh the website with the video and now you can find the video info in the addon icon, select the resolution and download it.

Do not use, BS should be able to download out of the box or get go, needing to download another program which my virus scanner blows up about is suspect.

It picks videos from sites that other famous downloaders does not. Great job!

It always fails to download videos so it's completely useless.