create-the-brass-oncerto/config/iceandfire/forest_troll_biomes.json

{
  "biomes": [
    [
      {
        "type": "BIOME_TAG",
        "negate": false,
        "value": "minecraft:is_overworld"
      },
      {
        "type": "BIOME_TAG",
        "negate": false,
        "value": "minecraft:is_forest"
      }
    ]
  ]
}