Red LED on Node MCU board

I am using the Node MCU board V1.0 as shown below for a IoT application. It sleeps always and once in a minute wakes up, posts some value to the cloud and goes to sleep. Working OK.

But when I am developing code and the unit is connected to the laptop, at times there is a Red LED on board that comes on ( the one near the CH340 chip ) . Tried to figure out the function of this LED.

Any idea why it is there ?

NODE MCU.JPG

Maybe this page will answer your question.

For the same reason that there is a LEDon pin 13 of most arduinos - to give you an led without having to add externsl hatdware.