This object is the identical StorageType convention applied to a row in the interface-to-virtual-context mapping table rather than the context table itself, indicating whether a given interface's assignment to a virtual context survives a reload. It matters because it tells an admin whether reassigning an interface to a different context via SNMP will persist or needs to be reapplied after every reboot. A permanent value here would mean that interface-to-context binding is locked in and its columns cannot be modified via SNMP at all, which explains an otherwise puzzling not-writable error when trying to move that interface to a different context.