This is an STL of an Prusa i3MK3 (s), perfect suited for the Prusa Slicer as an reference Build Plate as for Example. Or just print your Printer on your Printer for unlimt Printers.
For the CAD Model follow this link:
https://www.printables.com/de/model/307004-3d-modell-of-the-prusa-i3mk3-for-fusion-360
The author remixed this model.