Minecraft wiki entry for Generated_structures_data_file_format, associated text: The Village.dat, Fortress.dat, Temple.dat, Mineshaft.dat, Stronghold.dat, Monument.dat, EndCity.dat, and Mansion.dat files are located in the data folder of a Minecraft level and store information about the generation of villages, Nether fortresses, desert and jungle pyramids and witch huts and Igloos, mineshafts, strongholds, ocean monuments, end cities, and woodland mansions respectively, in the level. The structure data is stored in the chunk data.