Link for the companion pdf ($8 DMs Guild, 36 pages):
Domains of Delight (5e) - Wizards of the Coast | Dungeon Masters Guild (332 Mb)
Chapter 1 - Feywild Overview is really well done and full of imminently useful stuff. No clues or easter eggs to speak of, just reiterating that Summer Court = Seelie Court (Titania leads), and Gloaming Court = Unseelie Court (Queen of Air and Darkness leads).
Chapter 2 - Creating an Archfey is four pages that just felt paper thin to me. Not sure how much space was devoted in VGtR for making dark lords, but I feel like it was more comprehensive than this. No clues or easter eggs.
Chapter 3 - Creating a Domain of Delight is short but well done, definitely enough tables to provide you with a creative foundation to springboard off from. At the end, on the Domain Visitors table is mention of an arcanoloth searching for one of the
Books of Keeping – which seemed odd, unless the Queen of Air and Darkness is known for binding yugoloths?
Chapter 4 - Putting it All Together covers the archfey Yarnspinner, a paragraph on its domain Fablerise (which is apparently located in Thither within Prismeer), and a full page art spread.
And then there's 13 pages reprinting handouts from Witchlight's appendix: NPC Cards & Story Tracker. Which kind of sucks, because really that stuff should be a free download, in my opinion, for DMs who don't have easy access to a photocopier, who don't want to crack the binding on their book, or who are using a Roll20/Fantasy Grounds copy of the book but want the physical handouts.
But it's going to a good charity, so there's that.