I've been waiting for HDR and color management for like 5 years now and it feels like progress is dead in the water and now we've ended up with two custom implementations between KDE and gamescope. Heck, Kodi has supported HDR for ages when running direct to FB.
I know it's tricky but geez, by the time they release an actual protocol extension we'll already have half a dozen implementations that will have to be retooled to the standard, or worse yet we'll have a standard plus a bunch of fiddly incompatible implementations.
Those people can speak for themselves. I like getting plastered then walking around shirtless in below freezing temps. Makes me feel alive.