This is xnu-8019. See this file in:
Directory listing for xnu-8019//osfmk/ipc
Makefile
flipc.c
flipc.h
ipc_entry.c
ipc_entry.h
ipc_eventlink.c
ipc_eventlink.h
ipc_hash.c
ipc_hash.h
ipc_importance.c
ipc_importance.h
ipc_init.c
ipc_init.h
ipc_kmsg.c
ipc_kmsg.h
ipc_machdep.h
ipc_mqueue.c
ipc_mqueue.h
ipc_notify.c
ipc_notify.h
ipc_object.c
ipc_object.h
ipc_port.c
ipc_port.h
ipc_pset.c
ipc_pset.h
ipc_right.c
ipc_right.h
ipc_service_port.c
ipc_service_port.h
ipc_space.c
ipc_space.h
ipc_table.c
ipc_table.h
ipc_types.h
ipc_voucher.c
ipc_voucher.h
mach_debug.c
mach_kernelrpc.c
mach_msg.c
mach_port.c
mig_log.c
port.h