pumpkin-java-multiversion/assets/datapacks/26_2/data/minecraft/recipe/furnace_minecart.json

{
  "type": "minecraft:crafting_shapeless",
  "ingredients": [
    "minecraft:furnace",
    "minecraft:minecart"
  ],
  "result": {
    "id": "minecraft:furnace_minecart"
  }
}