Feat: Ratfolk Lore
Years of experience among ratfolk communities have made you nimble, and you've learned to run and hide when enemies threaten. You gain the trained proficiency rank in Acrobatics and Stealth. If you would automatically become trained in one of those skills (from your background or class, for example), you instead become trained in a skill of your choice.
You also gain the Additional Lore general feat for Ratfolk Lore.