As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT IN BASE MAINTENANCE: WEAR MARKS ALONG THE LEFT WING FIXED LEADING EDGE UPPER SKIN PANEL UPPER SURFACE, JUST INBOARD OF ENGINE STRUT. REMOVED AND REPLACED THE LEFT WING FIXED LEADING EDGE UPPER SKIN PANEL UPPER SURFACE. PER B737NG SRM 51-40-02-0G.