makeuseof had an article describing this:
I'm wondering if the color profile selection will allow the entire UI to change to the profile and not just while in certain apps.
PadOS 16 will introduce Reference Mode on the 12.9-inch iPad Pro. This will be handy for photo and video editors as it will let the display switch to sRGB mode to show the true colors of the media content when color grading or reviewing them.
I'm wondering if the color profile selection will allow the entire UI to change to the profile and not just while in certain apps.