This is xnu-8019. See this file in:
Directory listing for xnu-8019//bsd/dev
Makefile
arm/
arm64/
busvar.h
cpu_copy_in_cksum_gen.c
dev_perfmon.c
dtrace/
i386/
kmreg_com.h
ldd.h
mem.c
memdev.c
memdev.h
monotonic.c
munge.c
random/
unix_startup.c
vn/