Mental Floss - 2018-12-20

Once I enter the URL https://www.youtube.com/watch?v=9mCgb-ff3U0 and click the Find button, the next window (after a few seconds) is blank without any optoins except the "Select All" checkbox at the bottom and Back/Download buttons. Download doesn't start anything.

Is this more a bug or is therejust something I don't know about the process? It's worked with other vidfeos okay, but not this or some other UHD/4k videos.