From GameWatcher: “Rage 2 is out now and it’s a lot of fun, but it can be sometimes hard to see things sometimes once the wasteland gets dark. It can be a really dark game at times, so it’s understandable that players would be looking for a flashlight or Rage 2 Brightness options.”
Source: N4G PC Rage 2 Brightness Options – Is there a way to increase Brightness?