I think there is not much to explain about the Shell – Blank block, but I’ll do my best to try to fill this article with details about it.
NOTE: You can find the main page of the project, with the index of related links and articles here.
First of all, this is a block that mounts into the any of the two Shell MountingPoints (Front and Back of the rover).
It consist on a clean surface, without holes or any other thing that could be useless for your design.
You can check it partially assembled in the left part of the image.