EFI_ACPI_6_0_NFIT_GUID_RAM_DISK_SUPPORTING_VIRTUAL_DISK_REGION_VOLATILE

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
extern (C)
enum EFI_ACPI_6_0_NFIT_GUID_RAM_DISK_SUPPORTING_VIRTUAL_DISK_REGION_VOLATILE = GUID(0x77AB535A, 0x45FC, 0x624B, 0x55, 0x60, 0xF7, 0xB2, 0x81, 0xD1, 0xF9, 0x6E);

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