User-Facing Camera Light

The User-Facing Camera has a pale blue light that comes on occasionally. The User-Facing Camera is not being used when the light is on. I don't understand what this blue light means. Why does it go on? Does it have a purpose? It never happens in my home. I have been unable to find any reference to the pale blue light. My adult children and husband have iPhones and this pale blue light never goes on. Please explain what this blue light is and what triggers it to go on.