The kernel is in the xnu folder, this is a bunch of the underlying system, not just the kernel, but it's not the case that you can compile this all and get a wo

The kernel is in the xnu folder, this is a bunch of the underlying system, not just the kernel, but it's not the case that you can compile this all and get a working OS X Yosemite desktop (at least, I don't think you can but correct me if I'm wrong!)