As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LT WING SLIDE EICAS MESSAGE CAME ON SEVERAL TIMES WHILE AT THE GATE. DISARMED OFF WING EMERGENCY ESCAPE SLIDE SYS IAW TASK CARD 767-3-HAL005. OPENED LT OFF WING SLIDE COMPARTMENT DOOR. REMOVED UNWANTED MATERIAL FROM OFF WING SLIDE COMPARTMENT DOOR LATCHES. MANUALLY CYCLED LATCH SEVERAL TIMES. ALL INDICATIONS NORMAL. PSEU TEST OF PROX SWITCHES OK. REARMED IAW HAL 767-3-HAL005.