Included in the STL/3MF are the OMM mount for Aimpoint Micro pattern optics and the PIC picatinny rail riser. Both the mount and the riser can attach additional picatinny rails called Diving Boards for magnifiers, lasers, thermal or devices. There's a long and a short Diving Board depending on your needs.
Since this is 3D printed plastic and not metal, if you use basic PETG/PLA, you can absolutely expect the Diving Boards to wobble when you attach things on it, especially heavy magnifiers.
You can find videos of the real product to better understand how the mount/riser works.

Hardware needed for either the mount or the riser:

• 2 M4x30mm screws to attach the mount/riser to a picatinny rail. The screws are meant to tightly lodge into the clamps.
• 2 M5x15mm countersunk screws to attach the covers or the Diving Boards to the mount/riser. These screws are also meant to lodge very tightly.

Unless you're just printing this for decoration, use the hardest filament and with the highest infill that you can.