Mailbox Sensor's "Light Sensor"

On the Ring app the Mailbox Sensor has a screen for "Light Sensor" settings. But I'm not sure where or what it is, or what it's for. I'm guessing it's the little cloudy dome on the top. I thought it might light up at night, but it doesn't even with the the setting disabled for "activating **this light** during the day". So I guess the dome is only a light sensor and not also a light? (Even though the setting screen refers to "this light"?) So is the purpose of the light sensor actually for letting the Bridge know whether to activate **other** Ring lighting (to the activation of the Mailbox Sensor's motion sensor)? (FYI I don't plan to get any Ring lighting; I plan to activate my existing smart lighting with an Alexa Routine.)