As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHORT DURATION RATTLE FOLLOWED BY BURNED RUBBER SMELL NEAR FO SD WNDOW. FIRST OFFICER WINDOW NOISE. DEBRIEFED PILOTS ON ARRIVAL AND SAID ODOR OBSERVED ONLY FOR SEVERAL SECONDS. PILOT TURNED OFF FOOT HEATER. SMELL DISSIPATED. OPERATED FOOT HEATER IAW AMM DMC-B787-A-21-40-F5-02A-421A-A & SHOULDER HEATER REF. AMM DMC-B787-A-21-40-F5-04A-421A-A. ALL OPERATIONAL. NO SMELLS. OK TO CONTINUE.