KEY_VIRTUALIZATION_INFORMATION - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTREGAPI_H

typedef struct _KEY_VIRTUALIZATION_INFORMATION
{
    ULONG VirtualizationCandidate : 1; // Tells whether the key is part of the virtualization namespace scope (only HKLM\Software for now).
    ULONG VirtualizationEnabled : 1; // Tells whether virtualization is enabled on this key. Can be 1 only if above flag is 1.
    ULONG VirtualTarget : 1; // Tells if the key is a virtual key. Can be 1 only if above 2 are 0. Valid only on the virtual store key handles.
    ULONG VirtualStore : 1; // Tells if the key is a part of the virtual store path. Valid only on the virtual store key handles.
    ULONG VirtualSource : 1; // Tells if the key has ever been virtualized, can be 1 only if VirtualizationCandidate is 1.
    ULONG Reserved : 27;
} KEY_VIRTUALIZATION_INFORMATION, *PKEY_VIRTUALIZATION_INFORMATION;

#endif

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This structure is documented in Windows Driver Kit.