There is no prefab save in 1.0

The search asks how to create prefab buildings. 0 building notes, the Shifting Gears integrity post, and the FAQ language None of them announce a prefab save or a blueprint library.

Planning Mode places holograms and spends nothing until you commit materials. That is a sketch you build once. It is not a file you stamp across the map. Walls, doors, windows, roofs, and rails are modular parts, and integrity has existed since Shifting Gears. Repeating a house means repeating the parts, not loading a saved kit.

The accurate sentence is narrower: as of the 1.0 notes, no prefab save was published. If a later patch adds one, this page should say so and change its date.