This is xnu-6153.11.26. See this file in:
Directory listing for xnu-6153.11.26//bsd/dev
Makefile
arm/
arm64/
busvar.h
dtrace/
i386/
kmreg_com.h
ldd.h
mem.c
memdev.c
memdev.h
monotonic.c
munge.c
random/
unix_startup.c
vn/