WOW64T.H

The public symbol file NTKRPAMP.PDB for the original release of Windows 10 tells that the kernel is built with the WOW64T.H header at

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

and draws from it the following type definitions:

Line Number Type
163 enum _WOW64_SHARED_INFORMATION
354 struct _GDI_TEB_BATCH32
362 struct _GDI_TEB_BATCH64
384 struct _CLIENT_ID32

The header WOW64T.H is published in the “minwin” directory of the Windows Driver Kit (WDK) for Windows 10 in the original and Version 1511 editions.