Looks like it's owned by a ReactOS developer with quite a bit of experience in digging into Windows low-level internals: http://www.alex-ionescu.com/?page_id=2
This is not a file dump, but a file directory listing where he reproduces something Mark Russinovich did a while ago.
See also his tweet here:
https://twitter.com/aionescu/status/547322576947523586
quote: I've built an entire mapping of the Windows 10 Source Tree, similar to what @markrussinovich did back in the days