Bosch MUM9 dust cover for lid

The lid of the MUM9 has a big opening, this is a lid cover to avoid something getting in.

I tried to match the outline of the opening as good as possible, there are still some tiny deviations, but it is good enough that it has a nice fit – works well in PLA. 

If you would like to adjust it, I added the FreeCAD file – the end version is the second body contained in the file (the first body has a scaling problem).