From publisher blurb:
A little something extra for your PF2 game!
Spellcasters need additional choices to pursue concepts in critical success and failure where magic is concerned, and with Defensive Magic you'll find 8 new magics for specialists in protecting themselves, pitting their rivals against each other. You'll find spells up to 10th level spells so the most powerful casters can keep their secrets and guard their lives against their enemies!
The new Pathfinder Second Edition has a ton of customizable options, and the Just a Second line gives you about a page of new rules content to incorporate into your campaign. A set of feats, linked spells, clever magic items, and so on. No fuss, no muss, just new ideas and mechanics for GMs and players alike!