This is the documentation for Enlighten.
8. Light probe resolution
Enlighten automatically places light probes around actors that:
are lit by probes
have meshes
have the mobility Static
To see where the probes are, in the Show menu, enable Enlighten > Probes.
This shows the probes in the level.
The actors in this level use the default Enlighten probe resolution, which is sufficient for believable indirect lighting.In the World Outliner, double-click the actor Props_Balcony_6 to focus on it.
As the fire escape is in shadow, all the lighting on it is indirect light from probes. To make this easier to see, select Lighting Only.