Destination VRAM addresses for animated tiles. There are 6 bytes, 3 16-bit addresses, for each of the 8 possible animation frames (index = (frame & 7) * 6), and their values get stored to $0D7C, $0D7E, and $0D80 during the animation handling routine. (The last 6 bytes are actually unused, since SMW never uses animation frame 7 for anything.)