Question regarding HDR support for Linux-native X11 apps on Steam Deck

[Reonu]

In a game we're working on, we're looking into possibly adding HDR support in the future. However this leads us to a question.

• On Linux, HDR is only supported on Wayland as far as I know.
• For a Linux app to use HDR natively, it needs to be a native Wayland app
• However, Gamescope somehow supports HDR for Proton, which is an x11 app

So the question is:
Can other Linux-native x11 apps also support HDR through Gamescope somehow? If so, is there any documentation anywhere on this?
Thank you.