From Pathfinder Lost Omens Pathfinder Society Guide, which isn't enabled.

Armored Rest

FEAT 10

Prerequisites Swordmaster Dedication; trained in light, medium, or heavy armor

You've slept many nights in your armor and gotten used to it. You can sleep in armor overnight without being fatigued the next day. If you were already fatigued before sleeping, the armor doesn't prevent you from recovering from being fatigued.

Pathfinder Lost Omens Pathfinder Society GuideOGL