This read-only DisplayString reports the collection end time of a specific history bin, per its description, marking when this bin's counting period closed and, implicitly, when the next bin's period began. Together with cienaCesPmExtendedTxRxHistoryBinStartTime, this defines the exact time boundaries of the traffic and error counts recorded in this one bin, which matters when precisely correlating a PM bin against an external event log or another device's timestamped data. An engineer correlating a PM bin's counter values against a separate syslog event would use this end time, alongside the start time, to confirm the event actually falls within this bin's measurement window.