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

{
  "feature": "minecraft:blue_ice",
  "placement": [
    {
      "type": "minecraft:count",
      "count": {
        "type": "minecraft:uniform",
        "max_inclusive": 19,
        "min_inclusive": 0
      }
    },
    {
      "type": "minecraft:in_square"
    },
    {
      "type": "minecraft:height_range",
      "height": {
        "type": "minecraft:uniform",
        "max_inclusive": {
          "absolute": 61
        },
        "min_inclusive": {
          "absolute": 30
        }
      }
    },
    {
      "type": "minecraft:biome"
    }
  ]
}