I thought this was going to be in
but it is not.
But it reminded me of the question I had.
On newer cars, there is a blinking red light that can be found when the car is parked and key is out of ignition. It shows up better (only) at night, and is just a simple pimple type light.
What does this do, what is its purpose?
On my car, such a light indicates that the security system is on. True, it doesn’t really have a security system, but car thieves don’t know that… 
Seconded. My Landrover and Mitsubishi both do this… keys out, alarm on… flashing red light appears on dash to warn those thoughtful cautious lads with bricks that my car is alarmed.