Kernel uses id11 to determine behavior of svcBreak positive arguments. It will break instead of just force-exiting the process which is what happens on retail.
Kernel uses id12 when setting up the available RAM size. If bit0 is set, it will memset various allocated memory-regions with 0x58, 0x59, 0x60 ('X', 'Y', 'Z') instead of zero. This allows Nintendo devs to find uninitialized memory bugs.