As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FA'S IN THE BACK REPORTED A STRONG ODOR DURING THE TAXI OUT, RETURN TO GATE. PERFORMED IDENTIFICATION OF ODOR IAW TSM 05-50-00-810-831-A. OPS CHECKED AND RAN APU. AFTER RUNS COULD NOT DUPLICATE ODOR. ODOR WAS EXTERNAL BASED ON CREW INFO. ACFT OK FOR RETURN TO SERVICE