Wrath Classic has Large UI Changes ?

[Xrystal]

I can't see the blizzard source to this *large UI Change* being reported on wowhead.

https://www.wowhead.com/wotlk/news/u...phase-2-331015

And in particular this paragraph:

These changes are the same that happened with the Dragonflight launch in retail and are now arriving in Classic Wrath. These changes were testable during the Heroic+ and Ulduar testing these past few weeks.

I can't see anything outside of the patch notes and I can't see a reference to Dragonflight API being added.

What exactly was changed ?

Thanks for any info people can find, that I couldn't.