As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHEN WE WERE PERFORMING SB FOR "FLAPPER VALVE", THIS PART WAS FOUND ON FUEL CELL INNER FLOOR OF MIDDLE CELL. FOUND PN FOR SELF DISASSEMLED ITEM, IT WAS STAINLESS STEEL STRUT-REINFORCEMENT INTERNAL HORIZONTAL. THE PART WAS RE-INSTALLED.