| Koven |
It looks like a simple omission and they meant that every character is "trained" in unarmored defense. It would be nice if they would say this for every class, where they give the armor and weapons proficiency for each class.
The released the Pathfinder 2 Playtest stats for some of the iconics to include Ezren. They list his AC as 13, and he has a Dexterity of 14.
So AC = 10 + 2 (Dex mod.) + 1 (Trained in unarmored defense) = 13
If he wasn't trained in unarmored defense his AC wouldn't be 13.