AKA voltage mirror or voltage follower.
Note how the LED burns out due to the heavy load imposed by the lamp.
Toggle the switch to enable the opamp - it acts as a voltage buffer, protecting the LED while still providing enough power to the lamp.
This's circuit allows a low impedance circuit (right side) to follow (mirror) changes in voltage from a high impedance circuit (left side). Voltage buffers are the counterpart to current buffers. The difference is which side has low/high impedance.
