MM.H

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

d:\th\minkernel\ntos\inc

and draws from it the following type definitions:

Line Number	Type
40	struct _PHYSICAL_MEMORY_RUN
45	struct _PHYSICAL_MEMORY_DESCRIPTOR
147	struct _MM_SYSTEM_PAGE_COUNTS
1133	enum _PROCESS_VA_TYPE
1144	enum _PROCESS_SECTION_TYPE
1389	struct _MM_DRIVER_VERIFIER_DATA
1536	struct _UNLOADED_DRIVERS
1752	enum _MMLISTS
1763	struct _MMPFNLIST
2556	union _MM_STORE_KEY
3022	union _MM_PAGE_ACCESS_INFO_FLAGS
3023	unnamed struct for File in _MM_PAGE_ACCESS_INFO_FLAGS
3029	unnamed struct for Private in _MM_PAGE_ACCESS_INFO_FLAGS
3036	struct _MM_PAGE_ACCESS_INFO
3053	enum _MM_PAGE_ACCESS_TYPE
3060	struct _MM_PAGE_ACCESS_INFO_HEADER

The header MM.H is not known in any Device Driver Kit (DDK) or Windows Driver Kit (WDK).