I'm looking over the Cleric and Druid, and I am confused by their level 20 feats, Miraculous Power and Hierophant's Power. As far as I can tell, both classes have total access to their spell lists barring rarity restriction, so why do both feats say to add two 10th level spells to their list of spells known?
Take a look at each class' Spells Per Day chart (page 70 for Clerics, 81 for Druids). Note how those only go up as far as Level 9 spells?
Miraculous Power, Hierophant's Power (and I assume an equivalent one for Wizards and, possibly, Sorcerers) are the only way to get access to any tenth level spells.
EDIT: The class advancement tables (on page 70 for Clerics and 80 for Druids) bear this out as they make no mention of 10th level spells, but do list the other nine levels.
Null sheen, chummer. I got the impression that that was how 10th level spells would work back when they first previewed them in a blog post, I just had to check the tables myself as I was making that post to be sure I was remembering right.
EDIT: Ah; and there is a counterpart to those abilities for Sorcerer's and Wizards - Archmage's Might.