EVNTPAYLOAD.H

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

d:\th.public.fre\internal\minwin\priv_sdk\inc

and draws from it the following type definitions:

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