Based on the plans from the Panzer Tracts 6-3 book, these are replacement grills for 1/35 Maus tanks. They include accurate grate detail, orientation, bolt detail, etc.
Note that the grate detail is extremely fine and will need a high-resolution printer to print successfully.
stl files can be found here:
STL file 1/35 Panzer VII Maus detailed deck grills 
・3D print design to download・Cults (cults3d.com)
Thanks!
Matt