minecraft-src/data/minecraft/recipe/coal_from_smelting_coal_ore.json

{
  "type": "minecraft:smelting",
  "category": "misc",
  "cookingtime": 200,
  "experience": 0.1,
  "group": "coal",
  "ingredient": "minecraft:coal_ore",
  "result": {
    "id": "minecraft:coal"
  }
}