@minecraft/creator-tools/data/content/newitemjson/biome_resource.json

Minecraft Creator Tools command line and libraries.

{
  "format_version": "1.21.100",
  "minecraft:client_biome": {
    "description": {
      "identifier": "examplens:examplename"
    },
    "components": {
      "minecraft:sky_color": {
        "sky_color": "#00ff00"
      },
      "minecraft:ambient_sounds": {
        "loop": "ambient.waves"
      },
      "minecraft:water_appearance": {
        "surface_color": "#2d3784"
      },
      "minecraft:biome_music": {
        "volume_multiplier": 0
      },
      "minecraft:foliage_appearance": {
        "color": "#878d76"
      },
      "minecraft:grass_appearance": {
        "color": "#778272"
      }
    }
  }
}