Since it is low voltage it is relatively safe to mess with the exposed thin wiring.

Loosen one of the screws and carefully pull the wire(s) away from the screw, so the wire ends are just hanging in the air. Then go check for what doesn’t work anymore. Doorbell would be my guess but it could be something else that runs on low voltage.

When done, reconnect the wires under the screw head and snug the screw tight. If you do accidentally short wires or the tool between the two exposed screws there may be some sparks. While visually surprising, the mild sparking is not dangerous to you nor the transformer.