VARIABLE_NAME - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTEXAPI_H
#if (PHNT_MODE != PHNT_MODE_KERNEL)

typedef struct _VARIABLE_NAME
{
    ULONG NextEntryOffset;
    GUID VendorGuid;
    WCHAR Name[ANYSIZE_ARRAY];
} VARIABLE_NAME, *PVARIABLE_NAME;

#endif
#endif

View code on GitHub

This structure is documented in Windows Driver Kit.