terraform/testing/equivalence-tests/tests/nested_map_update/dynamic_resources.json

{
  "tfcoremock_nested_map": {
    "attributes": {
      "maps": {
        "type": "map",
        "required": true,
        "map": {
          "type": "map",
          "map": {
            "type": "string"
          }
        }
      }
    }
  }
}