This is a bracket for mounting things with cable ties. It's sized for an M5 flat head cap screw, but can likely fit similar sizes, or be drilled out (or modified with CAD) for something larger, like a 1/4-20. It works very nicely with 6 mm T-slot extrusion, which usually uses M5 hardware.

Print with your printer of choice. This is a simple enough part that layer height and fill won't matter too much. The surface fill near the edges of the countersink is the most likely spot to give trouble, but since you're strapping something to that face anyway, it doesn't need to be pretty.

The channels for the zip ties are arched, so it should bridge fine without support.