pf2e.fyi
From Pathfinder Guns & Gears, which isn't enabled.

Grit and Tenacity

FEAT 8
FORTUNEGUNSLINGER
Activity reaction
Frequency once per hour
Trigger You fail a Fortitude or Will save.

You call upon deep reserves of toughness and mental fortitude to power through an otherwise debilitating effect. Reroll the triggering save with a +2 circumstance bonus; you must use the second result.

Pathfinder Guns & GearsORC