Starting from 1.21, it was possible to make enchantments that repaired the enchanted item using a negative value for the damage_item component. However, as of 24w33a and up to the most recent snapshot 24w37a, this is no longer possible.

Steps to Reproduce:

1. Get the following item:

   /give @p minecraft:netherite_chestplate[minecraft:damage=591]
   

2. Enchant it with the following command:

   /enchant @p testing:repair_damage_negative_test
   

3. Hold the damaged item in your mainhand

Expected Result:
The item continues to have one durability point repaired every 20 ticks, like before.

Actual Result:
The item is not repairing itself over time, it remains at it's current durability amount.