From Pathfinder Lost Omens Cheliax, Infernal Inheritance, which isn't enabled.

Hard to Fool

FEAT 1

You're accustomed to seeing through shifting darkness and bewildering magic. You gain a +1 circumstance bonus on Perception checks against illusions as well as to Will saves against illusions and shadow effects.

Pathfinder Lost Omens Cheliax, Infernal InheritanceORC