Protocol for communicating mixed subpixel orientation?

Does wayland have a protocol for communicating the screen subpixel orientation that the window is drawing on?
Maybe even with juicey info on what part of the window covers which subpixel orientation?
And to tell you the truth I don't want to move the 7.5kg HP Z22i monitor at 3 am to test whether mixed orientation anti-aliasing is supported with some wayland protocol, but if it isn't I think this should exist or be in the works.

Proper subpixel anti-aliasing requires subpixel orientation information.
For anyone using their monitor in vertical and the other in horizontal orientation it isn't a matter of simply configuring the option once.
Yeah the user might override global freetype2 configuration, launch another app, change back the configuration.
But that's suboptimal, what if the user moves the window around.

I think such a change would be best served at a Wayland-protocol/DE level where the libGTK/libQT etc. can then read out the proper values/change of state?
I can see how part of this might have been already implemented for Linux Mobile space, where the screen orientation could change at any moment, but in those cases, there's just 1 subpixel orientation present and I don't know of any DE that implements per display subpixel rendering setting.

The way I understand things for now.
If this would have been implemented this would mean that for mixed subpixel orientation libGTK/libQT needs to render the fonts at the very least twice and mask out the result given what parts of a window intersect with which monitor.
I'm not sure how else this could be resolved for GTK/QT/ToolkitLibHere and it would be best if the conversation on this issue from this point on wasn't steered by me.