Works well....in Linux (openSuse / Ubuntu / Kubuntu) however the download shows NO links and suggests usage of Windows version to download videos as per link below

moz-extension://fd22d6b2-53ca-4116-aa0f-7611a7a3c821/novideo.html?lang=en&tabid=3&canaddvideo=1#

Tried to download video - Page URL for Kubuntu 18.04 / OpenSUSE Tumbleweed / OpenSUSE Leap 15.0

https://www.youtube.com/watch?v=jehyalhG2xo&list=RDlfP-bacUe4s&index=5