Every mapper knows what happens when a bright light is very close to a surface. The light "burns" it, creates an overbright spot. Very often you can't just move the light away from the surface because the light rays have to come from that spot, or because there are pretty shadows casted by that light. Lowering the light's intensity is also not an option because then you have a light that doesn't illuminate enough.
Thanks to warsow there is now a way to deal with that. It's called _extradist, a new entity key that adds an extra distance from light ray's origin and the surface they hit. This way you can have a light with high intensity next to a wall or ceiling and prevent the wall or ceiling from being "burned" by the light.
Note: it only works if you compile with q3map2 version that has this new feature in it, else it won't work.