[
  {
    "type": "mapgen",
    "//unexplored": "This mapgen exist only for suppressing 'No mapgen terrain exists for %s' type of errors on game start and shouldn't spawn ingame",
    "//omt_obsolete": "This mapgen is used for replacing obsoleted overmap terrain, normally it shouldn't spawn",
    "om_terrain": [ "unexplored", "omt_obsolete" ],
    "object": { "fill_ter": "t_nether_glass_floor" }
  }
]
