minecraft-assets/data/minecraft/worldgen/structure_set/nether_complexes.json

{
  "placement": {
    "type": "minecraft:random_spread",
    "salt": 30084232,
    "separation": 4,
    "spacing": 27
  },
  "structures": [
    {
      "structure": "minecraft:fortress",
      "weight": 2
    },
    {
      "structure": "minecraft:bastion_remnant",
      "weight": 3
    }
  ]
}