NtQueryInformationResourceManager - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTTMAPI_H
#if (PHNT_VERSION >= PHNT_VISTA)

NTSYSCALLAPI
NTSTATUS
NTAPI
NtQueryInformationResourceManager(
    _In_ HANDLE ResourceManagerHandle,
    _In_ RESOURCEMANAGER_INFORMATION_CLASS ResourceManagerInformationClass,
    _Out_writes_bytes_(ResourceManagerInformationLength) PVOID ResourceManagerInformation,
    _In_ ULONG ResourceManagerInformationLength,
    _Out_opt_ PULONG ReturnLength
    );

#endif
#endif

View code on GitHub
#ifndef _NTZWAPI_H

NTSYSCALLAPI
NTSTATUS
NTAPI
ZwQueryInformationResourceManager(
    _In_ HANDLE ResourceManagerHandle,
    _In_ RESOURCEMANAGER_INFORMATION_CLASS ResourceManagerInformationClass,
    _Out_writes_bytes_(ResourceManagerInformationLength) PVOID ResourceManagerInformation,
    _In_ ULONG ResourceManagerInformationLength,
    _Out_opt_ PULONG ReturnLength
    );

#endif

View code on GitHub

This function is documented in Windows Driver Kit here and here.