hmm, at first i thought it had something to do with masks. since there is actual a mask texture(As alternative to the normal), it might be to define which areas are shown from the mask texture?
Well it looks like the blue channel is being used for the aplha on a torn cloth. The red is most likely glowing bits, and the green is masking off a pretty big chunk of the model, maybe for some other material effect. It'd help if we could see the other textures with it and the model in game.