Cannot view HTML5 in new Quantum browser

I used to know how to manipulate but now I am old and the technology has passed me by. I get this:
image
omg…I don’t know how to do screen shots. but it says "your browser does not currently recognize anyof the video formats available. That’s a pain…any suggestions, folks?

Please visit this page http://youtube.com/html5

What do you see? You should see something like this https://screenshots.firefox.com/52Esvkj6j0nk7qsX/www.youtube.com

MSE & WebM VP9 has a red square…different from the second item…but what do I do with that web site??

Leslie A.Evans
603/499-3939

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