Comment by Zamundaaa (Xaver) a couple of hours ago. (AKA One of the most prominent KDE and Wayland Dev)
There will also be a new Display/HDR HackFest in around 2 weeks where most prominent Devs from different DE and companies like Valve, ADM and Igalia will attend. Hosted by the latter in La Coruña, Spain. https://www.phoronix.com/news/2024-Linux-Display-Hackfest-May
But doesnt KDE and weston already have HDR implementations? Yes but there are patched hacks. The protocol will finally make things clear and standard so it can be implemented by all the different parties.
The protocol in gitlab
Some app needs to implement this. How about Wine in winewayland.drv? :D Firefox is also an excellent candidate