2019-08-06 :
seems youtube changed some things… some days ago error about title, now it seems solved BUT can't find links for anything above HD resolution. And need to refresh before each download or it gets stucked to the previous link.

ten-months-ago :
Does what it says ;-)
But in settings/saving options
I can't manage to set a path for « save merged files in »
As soon as I write something there, got an error message « can't open folder ».
Letting it empty, merged files end up in « download » folder. ( Ubuntu 16-04 / 18.04 )