Being a weight fetishist (!) with our cars, what is not included in the design weight? Apart from all liquids, I cannot see what else could be missed off. If you know, do please tell.
In my car, fuel weighs in at 45 kg, oils are about 8 kg, and water about 20kg (never measured it but I know it is a lot!). Brake, clutch fluids and washer water may creep close to another 1kg. But that is another 74 kg without too much effort. Equivalent to the wife sitting in the passsnger seat (after she has binged out on an Indian take away meal)!!!!!!