These are single and double “Part A” offset snap connectors for Multiboard made to hang from Benjamin Kott's “LED Riser Modular” for the P1S and X1C. 

As stated in the Multiboard documentation:

The “8 mm Offset Snap” creates an 8 mm gap between your Multiboard and a surface when using the “off-a-surface” mounting system. This piece usually goes on the corners of your Multiboard.

Printing Guidelines:

The printing orientation is as provided in the file. The print has been designed to be “3 wall perimeters” in wall thickness. Printed at a layout height of 0.2 mm. It doesn't need printing supports. Use the default 15% infill. This part has been designed with a tolerance of 0.25 mm. Your printer will need to be able to bridge gaps of up to 30 mm for some designs.

It's advised to print out the corresponding “Part B” connectors to match these “Part A” connectors, and additional standard offset snaps to give the bottom of your Multiboard that necessary 8mm clearance from the side of the printer.