https://buy.garmin.com/en-US/US/p/550821#overview
They are lights that automatically turn on when needed. Thus, people don't need to bring a lights for the bike they rent, in case it gets dark, etc. Right now, the Biketown bikes don't include any lights on them, so you basically either bring your own or just don't ride them in the evening.
There are of course other features, like automatic brightness adjustment etc. They can be like daytime running lights for your car.
