This is a simple cover/shroud for 140mm PC case fans, in order to prevent dust from simply falling in, or to redirect air. There's a small ramp on the inside opposite of the hole, just to help push some of the air from the far side towards the hole.
It is meant to be used on the outside of the case, with the fan screws holding it in place, although I recommend trying to use slightly longer screws if you have them around, since the cover/shroud acts as a 1mm spacer. In the pictures, I used normal 10mm long fan screws.
Make sure you print it with the flat side down and the screw holes up, just like how the model comes by default, and enable supports.
I printed two of them with PLA for the top exhaust fans of my Fractal Design Focus G and it works well for that. ~100g per shroud/cover.
The author marked this model as their own original creation.