Generally, if nothing else works, in a desktop browser, I right click the video area, and Inspect Code or something like that, which brings up the browser’s code inspector.

Then I look for a string “.mp4” which will be the filename. It might be buried under several layers of html, but be persistent clicking backwards and forwards through the HTML, and it shows up eventually.

Try to open that URL in a different browser tab and save it from there.

Sometimes that searching doesn’t work though, especially if it’s passing parameters to a custom media player.

All I see on that page is a link to YouTube.

The URL in the OP just sent me to the homepage.

I think one has to be logged in to see the actual lesson page.