This read-write enumeration, with values nil or clear, is a command object rather than a stored counter: writing clear(2) resets all of the OC-3 statistics group's counters at once. It exists so an admin can zero out accumulated error/traffic counts after a known event (like a fiber repair) instead of waiting for the 15-minute window to roll over naturally, but the description notes it only takes effect when hcxStatsControl is set to wrapCurr. For instance, after replacing a damaged OC-3 transceiver, a technician sets hcxOc3StatsClear to clear(2) so subsequent Far End Block Error counts reflect only post-repair behavior.