This is a cover for the Anet A8 Ribbon cable if you are doing a relocated LCD mod and want to cover the cable so nothing hits it. Printed on its back.
Use whatever infill you want, it doesn't need to be strong as it isn't supporting anything. If you use a low infill, don't use a drill to screw it down to the surface or you might crack the plastic. Just hand tighten with a screw driver.