I tried it and I don't like the UI looks confusing so uninstalled and currently try IDM.

nie jestem pewien czy to wina stron z których ściągam filmy czy rozszerzenia, ale pobieranie bardzo często się zatrzymuje, a nawet przerywa, że nie da się wznowić

I just downloaded this Addon after I was using the "Easy Youtube Video Downloader Express" for some years and now is not working. So I decided to give this one a try. It works and it can downloads High Quality videos from the YouTube. "But Remember to choose the (Video DownloadHeper COMPANION APP) to download the videos better".
* The things that I DON'T like is that I couldn't find the "DESKTOP" location to download my videos there. There are only the Disc Drives. And that the Converted videos have a BIG watermark QR code on the Left corner side and covers much of the video.