Comment by lxgr

For more information on the different ways to encode HDR content in images, together with examples for each, I've found this article very useful: https://gregbenzphotography.com/hdr/

And this explains how Apple implements this feature on non-OLED/mini-LED screens (and, in my observation, at least still to some extent even on mini-LED): https://prolost.com/blog/edr