As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB FROM KDTW THE R REV UNLOCKED MSG ILLUMINATED. THE FLIGHT CREW PERFORMED THE QRH AND DECLARED AN EMERGENCY. THE ACFT WAS ROUTED BACK TO KDTW WHERE AN OTHERWISE UNEVENTFUL APPROACH AND LANDING WAS MADE. MX INSPECTED THE ACFT AND DEFERRED THE RT THRUST REVERSER. THE ACFT WAS RELEASED FOR SERVICE.