Various parts of Kingdom Keys are data driven using JSON files which which allows for customisation via a data pack. See how to create a data pack here. The namespace folder for Kingdom Keys is simply kingdomkeys
Here is a list of every data driven element:

• Keyblades
• Drive Forms
• Leveling Paths
• Magic
• Moogle Shops
• Synthesis recipes
• Limits
• Organization Weapons
• Castle Oblivion (Not fully functional yet)

Keyblades

Keyblade data is in the keyblades folder, here is the JSON file structure:

• (string) ability: the ability given by the Keyblade.
• (object) base_stats:
  • (integer) mag: the base magic stat before upgrades.
  • (integer) str: the base strength stat before upgrades.
• (string) description: the localisation key for the description displayed in the tooltip.
• (string) keychain: the keychain item used to summon the Keyblade.
• (object array) levels: the order of the elements is important as it is the level order so the 2nd element is for the level 2 upgrade.
  • (integer) mag: the magic stat for the level.
  • (integer) str: the strength stats for the level.
  • (object array) recipe: the material cost to upgrade.
    • (string) material: the material item.
    • (integer) quantity: the quantity of the material.
• (float) reach: the block reach of the Keyblade.

Drive Forms

Drive Form data is in the driveforms folder, here is the JSON file structure:

• (integer) cost: the Drive Point cost to use the Form.
• (integer) ap: the Anti Point increase (can be negative).
• (bool) can_go_anti: whether using the Form can trigger Anti Form.
• (bool) can_use_magic: whether magic is usable in the Form.
• (float) str_mult: the strength multiplier when using the Form.
• (float) mag_mult: the magic multiplier when using the Form.
• (float) speed_mult: the movement speed multiplier when using the Form.
• (integer array) level_up: the exp needed for the Form levels.
• (string array) abilities: the abilities the Form has.
• (string array) base_levelup_abilities: the abilities learnt for the player when levelling up.
• (string array) driveform_levelup_abilities: the abilities learnt for the Form when levelling up.