The file is available from:
https://cernbox.cern.ch/index.php/s/Q6eiMk1Q1oFTxG8.
The file is too big to be displayed in the browser, so save the file, Discover.mkv, and play it locally.
A file with the .MKV file extension is a Matroska Video file. It's a video container much like MOV and AVI, but also supports an unlimited number of audio, picture and subtitle tracks (like SRT or USF).
On a Mac I play it with "Elmedia player".