The short explanation
A color space defines which colors a signal can describe. The old standard, Rec.709, covers a modest range. BT.2020 — also written Rec.2020 — covers a much wider one, and is the container for UHD and HDR.
No consumer display reproduces all of BT.2020. In practice content is mastered inside a smaller target, usually DCI-P3, and carried in the BT.2020 container.
Where you run into it
What the display is told about the color space determines how it interprets every value it receives. Get the container wrong and colors shift — typically over-saturated, with skin tones going red.
This is precisely the LLDV primaries trap: send DCI-P3 to a display expecting BT.2020 and it applies the wrong interpretation to the correct data.
How the DR HDMI 8K handles it
A large part of the DR HDMI 8K's EDID library is explicitly BT.2020: 4K60, 4K50, 4K30, 4K24 and 1080p tables in BT.2020 with and without HDR. In the Dolby Vision section, BT.2020 is one of the selectable primaries, and it is usually the right answer when LLDV colors look over-cooked.
Want to test your own HDMI chain?
The DR HDMI 8K is sold through the HDFury.eu web shop.