As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT 2917, AIRFRAME VIBRATION FELT ABOVE 190 KNOTS. AIR RETURN TO DTW FOR INSPECTION. MAINTENANCE FOUND LAVATORY SERVICING DOOR PANEL OPEN, RESECURED. PERFORMED VISUAL INSPECTION OF EXTERIOR OF A/C FOR DISCREPANCIES, NONE NOTED. ALL CHECKS GOOD.