OBP.H

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

d:\th\minkernel\ntos\ob

and draws from it the following type definitions:

Line Number Type
317 struct _OBJECT_HEADER_HANDLE_REVOCATION_INFO
629 struct _OBJECT_REF_TRACE
639 struct _OBJECT_REF_STACK_INFO
652 struct _OBJECT_REF_INFO
668 struct _STACK_TABLE
962 struct _OBP_SYSTEM_DOS_DEVICE_STATE
1147 struct _OBP_LOOKUP_CONTEXT
2258 struct _OBP_SILODRIVERSTATE

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