This object contains the header comment that the agent prepends to the backup and snapshot files. By default, it will contain a zero length string. It shall also be set to a zero length string by the agent when any operation is started. As the operation proceeds, this object shall be set to the generated string for backup and snapshot operations and to the received string for restore operations. The string shall then remain unchanged until the next operation commences. If the file being restored does not contain a header, this object shall contain the zero length string when the operation has completed. This object shall be read-only when an operation is in progress. That is when a3ComBackupAction is not notActive(1)