With this datapack, master villager can be given a mastery tome of their profession to unlock a new trade : a repair token for your stuff.
Mastery tomes are crafted with an emerald block, a book and the corresponding work station. When you give master villager their mastery tome, they will unlock a new trade that allow you to get the item you're holding to be repaired. Supported villager are armorer, fletcher, leatherworker, toolsmith and weaponsmith. While unenchanted items are easily repaired, enchantments will make it harder for the craftsmen to repair items. But don't worry, as you trade with them, they gain more and more experience, allowing for better repairs.