BETTER ERROR MESSAGES NEEDED! YT video visible > Click on "yD" > "Download Panel" > right half of video replaced with orange panel simply saying "pathname is undefined". This is as of Oct. 24 2020, using Firefox 82.0 on a Mac. It sounds like you're in a battle trying to keep up with YT changes, which I understand. But please provide better error messages to let us know what's going on.