Maestro Concert Grand v2 is a big giga bank using 792 stereo samples of a concert piano, a Yamaha CF3, recorded with two Neumann KM84 microphones, disposed in X/Y, with 5 velocity layers, and weighs 932 MB !
The piano alone, without release samples, weighs 887 Mb and 440 samples. The release samples are 352 and weigh 45 MB. You can play with or without them.