this is a scam, not working

No stars. Useless unless you pay them money. Find another downloader.

Doesn't let you download high resolution videos.

useless, does not let you download MP3's or good quality videos.

Won't download any mp3 without paying.

раньше шляпа набучевская была, та ще за гроши - ще тоже шляпа. снёс

no matter which kind of download you chose, you always get a lame excuse about changed youtube formats and are urged to pay for the full service. Hence this is not a free addon, it's payware.

need to pay for using this app! not recommend!

Absolute trash, doesn't download past 720p unless you "upgrade," doesn't support 4k download in any context. Garbage.

Only allow download of videos that have been already downloaded recently by a paying user.

They ask for money for something that is not real. Any other YT downloader dosn't have this problem.

a fuerzas te quieren hacer descargar aplicaciones, pesimo servicio

MP3には第3者のアプリがいる。

fine tool to get mp3's - works like a charm; my latest use is some months ago; not working anymore for me

Is only willing to download at 360p, and tells some lie about how the conversion "needs powerful server infrastructure". No it does not. That is a flat out lie. It should just do the conversion on my machine. Absolutely ridiculous.

Someone else recommended a software called Jdownloader. It isn't as convenient as a browser extension but it works pretty well.