Incidental Learning Strain Strain Milestone card back/front, from Survivors of Death 1.
Strain milestones are a way for player exploits to permanently alter the future of their games. During the settlement phase, any unreached strain milestone cards are placed on the settlement board over the "Check Milestones" step.
During this step, check the strain milestone cards first. If any of the card's milestone conditions have been reached, resolve it's permanent effect and remove the achieved strain milestone from the game. They can never be used again in any campaign.