The value saved in this variable is: If the copied file is from the NE's file system it is the value of fileSystemSignatureBoot of the copied file. Otherwise (the copied file is external), it is the value of snmpEngineBoot at the time when copy operation is completed. For Running configuration file: The variable is also updated with the device's snmpEngineBoot whenever the Running Configuration file is changed (by user). After reboot, the value is copied from fileSystemSignatureBoot of the file copied to the Running configuration (e.g. startup-config, rollback-config, user-default-config, or factory-default-config). For Factory Default configuration file: The variable denotes the value of snmpEngineBoot when the file was uploaded to the NE.