It's dodgy software. It got acquired and got some spyware/adware/toolbars embedded. Don't trust.

Personally, I removed the older version I had, fearing it would auto upgrade and auto install malware.

It's a download manager for shared hosting sites, mostly used for downloading movies/shows/games. It can get videos from youtube, dailymotion and a hundred sites but it's not the main purpose. Users are willing to try anything to get their latest tv show, there is too much money in bundling adware to ignore. The software was great once upon a time, then it got popular, eventually the author sold out.

There are adware free installers you can find:

https://jdownloader.org/jdownloader2

nice. They kind of hide this from the main download link.

Get the .jar, use only the .jar. It self-updates and everything. It's a shame about the crapware-laden installer, though, it's an excellent utility otherwise.

It's not exactly the same category of software. It's a download manager, not a video extractor/scrapper.

It should be noted though that it has a fairly powerful built-in scrapper supporting video download from numerous sites. Unfortunately checking the code it seems to be closely integrated to the rest of the program, so someone cannot make (easily) a console utility based on it.

Thanks!