How the Covers Are Chosen in Xali's Enchanted Books

The pack ships an item definition at assets/minecraft/items/enchanted_book.json. That file uses a minecraft:select model that reads the item's minecraft:stored_enchantments component and matches it against a list of cases, one case per enchantment/level pair. Each case points at its own model, and each model points at its own texture under assets/minecraft/textures/item/.

In practice this means:

• A book holding exactly one enchantment at a given level gets that enchantment's custom cover, e.g. a book with only Sharpness V shows the Sharpness V art.
• A book whose stored enchantments do not match any case falls back to minecraft:item/enchanted_book, the normal vanilla texture. This is what you will see on books that carry several enchantments at once, such as combined books made in creative or handed out by some modpacks.

Because the selection is driven entirely by a vanilla component, there is nothing to configure and no mod involved - the game does the matching itself.