Worked for a few days. Suddenly stopped, and won't download anything without the intrusive companion app.
Borderline malicious.

No funciona, te pide que descargues mas software, fuera de este sitio.

Now you need to install their sketchy add-on app to download videos. As if that weren't enough - after a 4 hrs long download... they tell me they've added a QR code to my video as I didn't purchase a license. Now had I known about this from the beginning, I could've made an informed decision about wheter to use your service or not, couldn't I? I certainly am not going to donate even a cent of my money now, after hours wasted. Thanks for nothing, disinstalled.

Awful watermak now. Just use yt-dlg instead : it's powerful and full opensource, even if it's not browser integrated.

Tries to install an additional app instead of working as an extension

They now have a watermark paywall to remove it -10/10

Demands a companion app instead of working as an extension, would not recommend.

How the hell do I download this extension? I've used it for years, but now it seems to want an update. There seems to be no obvious way to do this.

I wouldn't recommend it. I was able to download ONE video and then they started to beg for me to pay money to register, putting a freaking barcode on the video, AND you will be forced to download their app. Overall it's s$*@

TODOS os vídeos ficaram com um QR Code.
Simplesmente péssimo.
Não baixem.

The add-on coerces users to download a companion app. The video files for which it suggests it's companion app is required are easily downloadable by the direct http address of the video, proving further that the app uses disinformation to achieve its goal of installation of its "companion app".

The companion app analysis is shown here which contains a range of malware activities;

Malware the add-on attempts to make users download; https://github.com/aclap-dev/vdhcoapp/releases/download/v2.0.10/vdhcoapp-2.0.10-win7-x86_64-installer.exe

https://hybrid-analysis.com/sample/d0840f71cd86f68883e390efbacf304568a78cabfb3df7357ef73eb7fa2eb45b

https://hybrid-analysis.com/sample/a0676a9cd8b6a70e7c113d55b53f07ee96d1560c7e18d7c2b125d529a08085f5

Latest update has made it necessary to also update Companion App. It says you just need this for ADP downloads, but even if you select a HLS download it also insists on the App.
Then your download ADP gets "Watermarked" with a QR code, and you have to pay to remove.
Claims Watermark is only on ADP, but if you download HLS, only get Audio...

Used to be great. Now it's not. Pick one of the many other options.

watermark ruins videos

Used to work great, then got enshitified. Requires app to download and forces payment to remove watermark.