KI.H

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

d:\th\minkernel\ntos\ke

and draws from it the following type definitions:

Line Number Type
129 struct _KTIMER2_COLLECTION
5749 struct _KSECONDARY_IDT_ENTRY

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