The public symbol file NTKRPAMP.PDB for the original release of Windows 10 tells that the kernel is built with the GUIDDEF.H header at


and draws from it the following type definitions:

Line Number Type
22 struct _GUID

A header named GUIDDEF.H is among the headers in the publicly available Windows Driver Kit (WDK) for Windows 10. It is there in the “shared” subdirectory with many other headers that are intended for use in both kernel-mode and user-mode programming.