ReactOS is too buggy to be used as a daily driver for your operating system, but it's awesome as Windows Kernel reference code. You want to know what a Kernel-mode function does? Ether read the documentation, or look at what ReactOS does. (Yes, leaked Windows code exists too, and it's even on freakin Microsoft-owned-Github of all places, but you can't legally look at that stuff!)
Hi, it's me, Mr Hair Splitting: to the best of my knowledge it's not illegal to read the source, but it would be illegal to use the source in your own application because you didn't author it or have a license to it
That's actually why the Wine and ReactOS folks want to disqualify folks who have read the source for fear they would inadvertently "borrow" implementation ideas, versus being able to explain to a judge how they, themselves, came up with the implementation. The key point is that Wine and ReactOS merely disqualify someone, not imprison or fine them
