minecraft-assets/data/minecraft/worldgen/placed_feature/potato_cloud.json

{
  "feature": "minecraft:potato_cloud",
  "placement": [
    {
      "type": "minecraft:rarity_filter",
      "chance": 10
    },
    {
      "type": "minecraft:in_square"
    },
    {
      "type": "minecraft:cloud"
    },
    {
      "type": "minecraft:biome"
    }
  ]
}