I am not 100% sure of what you mean, but I picked up a 2005 Jeep Wrangler brocure a couple years back while I was in college to read in class one day. In the list of colors was "Mud". The picture of the color was the driver corner (hood/fender etc.) of a white Jeep covered in mud.
I would assume its a joke, but if your really curious about this color, go to your local Jeep dealer and ask for a 2008 Wrangler brocure. If they dont have them yet, ask them when they are coming in, and pick one up then. It will have every color available to order, and even a nice picture of what it will look like