gEfiVendorKeysNvGuid

GUID used to "VendorKeysNv" variable to record the out of band secure boot keys modification.
This variable is a read-only NV variable that indicates whether someone other than the platform vendor has used a
mechanism not defined by the UEFI Specification to transition the system to setup mode or to update secure boot keys.
Include/Guid/AuthenticatedVariableFormat.h

GUID Information

GUID's Guid Name	GUID's Guid
gEfiVendorKeysNvGuid	{ 0x9073e4e0, 0x60ec, 0x4b6e, { 0x99, 0x3, 0x4c, 0x22, 0x3c, 0x26, 0xf, 0x3c } }

Refer to Header File

SecurityPkg/Include/Guid/AuthenticatedVariableFormat.h