HDR Previewing on Mac Display?

This update also improves HDR previewing when the Mac display color profile option is enabled on your computer giving you greater confidence in your monitoring. In addition, when using both optimized media and performance mode at the same time, you will now get improved scaling and aspect ratio display during playback.

What exactly does this mean? And, how is it exactly enabled. I'm curious to test this out on my iMac since supposedly I can watch iTunes movies in 4K HDR on it. So, I'm curious to see whether this means I can now monitor HDR on the display as well when grading in Resolve. Will be interesting to test even if it's not the most optimum for HDR grading since you still want a proper grading display.

This update also improves HDR previewing when the Mac display color profile option is enabled on your computer giving you greater confidence in your monitoring. In addition, when using both optimized media and performance mode at the same time, you will now get improved scaling and aspect ratio display during playback.

What exactly does this mean? And, how is it exactly enabled. I'm curious to test this out on my iMac since supposedly I can watch iTunes movies in 4K HDR on it. So, I'm curious to see whether this means I can now monitor HDR on the display as well when grading in Resolve. Will be interesting to test even if it's not the most optimum for HDR grading since you still want a proper grading display.

It is neither possible to view movies in HDR nor to grade HDR footage on an iMac.