Medium Armor Master

Medium Armor Master
Feat
Prerequisite: Level 4; Proficiency required

You gain the following benefits.
Dexterous Wearer.
While you're wearing Medium armor, you can add 3, rather than 2 to your AC if you have a Dexterity score of 16 or higher.

Source: Player's Handbook (2024) (XPHB), page 205