pf2e.fyi
From Pathfinder Lost Omens Divine Mysteries, which isn't enabled.

Retributive Focus

FEAT 18
CHAMPION
Activity free action
Prerequisites Desperate Prayer
Frequency once per day
Requirements Your focus pool is currently empty.

Your enemy's offenses fuel your righteous power. When an enemy triggers your champion's reaction, you regain 1 Focus Point.

Pathfinder Lost Omens Divine MysteriesORC