Great mod for working with lighting. Originally written by @nodrog6 (original thread here), was maintained by @RealGecko for a while.
Adopted by Linuxgurugamer.
Thanks to github user @kujuman, who had updated it (but it still had a problem with the lighting), I have been able to restore full functionality to it.
Add day and night modes to the VAB and SPH! Turn off the lights in the editors! Works at all upgrade levels!
LightsOut takes the existing VAB and SPH asset