Not sure you will find the lighting in the PostProcessing Volume that HAS to be supplied with the map. Unless it’s a component or something I could not find any relevant data when I had a looksie earlier, but I didn’t really look very hard.
There will be a PostProcessing Volume in all maps, there is also a day night light actor as well. In UDK and UE4+ you either bake your lighting or you do some heavy messy post processing each time you load the game. If you look through all the textures they have all the ambient occlusion already baked into them, I just assumed they baked lighting. It seems a bit weird that they would do lighting on the fly, but the entire environment is asynchronously streamed into the world, so you can’t bake lighting without the objects pre existing in the scene.
So that being said, there is an option that says how far and wide the lighting is, where it starts and where it stops. Either it’s to do with day and night, i.e. Day here Night there. Or a post processing volume. I just hope it’s not part of the environment streaming, as that would be a lot harder to find.