My Apple Studio Display with DVI has a green LED that is visible when looking from the rear of the display. What is this LED used for?

There are two LEDs on the Apple Studio Display DVI. The LED visible from the rear of the display is a visual indication that the display's controller circuitry is on and functioning properly.

The status LED visible from the front of the display is a power indicator light. A solid green LED indicates that the display is powered on and ready to display an image. An amber LED indicates that the display is in the energy saving sleep mode.