Experience Orb

Experience (EXP or XP for short) can be gained from defeating mobs or performing many kinds of other actions. Experience has no direct effect on the player character, but it can be used to enhance their equipment through enchanting, or by using an anvil to repair, rename, or combine enchantments on equipment. Most sources of experience are produced in the form of experience orbs. In Java Edition, experience gained affects the player's score on the death screen.
Experience orbs also recover durability on items with Mending that are being worn or are in-hand.