HEAP.H

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

d:\th\minkernel\ntos\inc

and draws from it the following type definitions:

Line Number Type
51 struct _HEAP_UNPACKED_ENTRY
162 struct _HEAP_EXTENDED_ENTRY
186 struct _HEAP_ENTRY
229 struct _HEAP_ENTRY_EXTRA
272 struct _HEAP_FREE_ENTRY_EXTRA
283 struct _HEAP_VIRTUAL_ALLOC_ENTRY
291 struct _HEAP_FREE_ENTRY
349 struct _HEAP_UCR_DESCRIPTOR
359 struct _HEAP_SEGMENT
389 struct _HEAP_LOCK
390 unnamed union Lock in _HEAP_LOCK
402 struct _HEAP_TAG_ENTRY
411 struct _HEAP_PSEUDO_TAG_ENTRY
417 struct _HEAP_COUNTERS
454 struct _HEAP_TUNING_PARAMETERS
534 struct _HEAP
681 struct _HEAP_STOP_ON_TAG
691 struct _HEAP_STOP_ON_VALUES

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