minecraft-assets/data/minecraft/recipe/waxed_exposed_copper_grate.json

{
  "type": "minecraft:crafting_shaped",
  "category": "building",
  "key": {
    "M": "minecraft:waxed_exposed_copper"
  },
  "pattern": [
    " M ",
    "M M",
    " M "
  ],
  "result": {
    "count": 4,
    "id": "minecraft:waxed_exposed_copper_grate"
  }
}