You should probably remove this from the first post. No questions whatsoever were answered today, and neither in the past few streams as far as I could see in the past broadcasts.Starting now, during every ESO Live we’ll hold a Q&A where we’ll answer some of your questions about the game
What actually happens is that the game internally renders HDR lighting and then in order to display this dynamic range on TVs (which are incapable of displaying the full range) they have to tone map the image to a limited range. For normal TV this range is 0-255 and games have been doing this for years and years since Half Life 2.
However the new HDR TVs are capable of displaying range from 0-1023 for HDR10 and higher for Dolby HDR but in order to use this ability the developers now have to tone map to this range instead of tone mapping to be displayed on 0-255. This process is not automatic and this is why developers need to support HDR displays in order for the games to use them. And yes you guessed it right even HDR TVs don't really display the full range it's just that they are capable of displaying a lot more range than older non HDR TVs.