ALPCP.H

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

d:\th\minkernel\ntos\lpc\alpc

and draws from it the following type definitions:

Line Number Type
595 struct _ALPC_HANDLE_ENTRY
601 struct _ALPC_HANDLE_TABLE
649 enum _BLOB_ID
665 struct _BLOB_COUNTERS
672 struct _BLOB_TYPE
752 struct _BLOB
782 unnamed union for u1 in _BLOB
784 unnamed struct for s1 in u1 in _BLOB
1577 struct _KALPC_RESERVE
1608 struct _KALPC_SECURITY_DATA
1617 unnamed union for u1 in _KALPC_SECURITY_DATA
1619 unnamed struct for s1 in u1 in _KALPC_SECURITY_DATA
1630 struct _KALPC_SECTION
1641 unnamed union for u1 in _KALPC_SECTION
1643 unnamed struct for s1 in u1 in _KALPC_SECTION
1657 struct _KALPC_REGION
1667 unnamed union for u1 in _KALPC_REGION
1669 unnamed struct for s1 in u1 in _KALPC_REGION
1685 struct _KALPC_VIEW
1700 unnamed union for u1 in _KALPC_VIEW
1702 unnamed struct for s1 in u1 in _KALPC_VIEW
1921 struct _KALPC_HANDLE_DATA
1933 union _KALPC_DIRECT_EVENT
1943 struct _KALPC_MESSAGE_ATTRIBUTES
1958 struct _ALPC_COMMUNICATION_INFO
2046 struct _KALPC_MESSAGE
2070 unnamed union for u1 in _KALPC_MESSAGE
2072 unnamed struct for s1 in u1 in _KALPC_MESSAGE
2220 struct _ALPC_COMPLETION_PACKET_LOOKASIDE_ENTRY
2226 struct _ALPC_COMPLETION_PACKET_LOOKASIDE
2345 struct _ALPC_COMPLETION_LIST
2427 struct _ALPC_PORT_REFERENCE_WAIT_BLOCK
2436 struct _ALPC_PORT
2654 unnamed union for u1 in _ALPC_PORT
2656 unnamed struct for s1 in u1 in _ALPC_PORT
3953 struct _ALPC_DISPATCH_CONTEXT

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