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


and draws from it the following type definition:

Line Number Type Remarks
347 enum _TRACE_INFORMATION_CLASS line 31617 in WDM.H
line 15998 in NTOSP.H

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