Chrome and Firefox play HDR videos just fine, it's one of the first things I did when I opened the package.

Here's a good one if you want to fall in love with the display: https://www.youtube.com/watch?v=1MieluM0c6c&t=28s

And here's a good one if you want to feel a little disappointed: https://www.youtube.com/watch?v=AYtvehF9-Z8&t=20s