Adds custom item properties, for now it is only submerged predicate that lets items change when the player is underwater. More properties coming soon.

example with Weskerson's torches

how to use on

minecraft/items

{
  "model": {
    "type": "minecraft:condition",
    "property": "rj:submerged",
    "on_true": {
      "type": "minecraft:model",
      "model": "minecraft:item/underwater_item"
    },
    "on_false": {
      "type": "minecraft:model",
      "model": "minecraft:item/normal_item"
    }
  }
}