When making a custom enchantment or modifying a vanilla enchantment, one can set the applicable slots for the enchantment to be "any". However, this does not seem to take into account the slot for saddles, preventing any enchantment from taking effect if placed there.
Steps To Reproduce:
1. Load into a world with the saddle testing datapack attached. It adds saddles to the enchantable/equippable tag, and adds a new enchantment called "test saddle", which adds +2 to the user's movement but also has the prevent_armor_change effect component.
2. Find/spawn a horse and tame it.
3. Give it a standard saddle to observe the riding capabilities.
4. Enchant the saddle with "test saddle". Notice how the movement effect gets applied when the player is holding the item, signified by the FOV change.
5. Place the enchanted saddle into the horse's saddle slot, and observe any changes.
Expected Result:
The horse gets an increase to it's movement speed, but the saddle cannot be removed afterwards.
Actual Result:
No change to the horse's movement speed attribute, and the saddle can be freely removed from the horse.