Shadowcams are at the bottom of the camera list, and each one is positioned at a light. Unfortunately they are named by some bizarre convention that defies logic, but once you figure out which one is which, you can rename them to match them to the light.

When you look through a shadowcam, you see what the light is "seeing." It's fascinating at worst, and extremely helpful when positioning lights at best. They deserve a tutorial, but I've never seen one. If I remember correctly, they weren't even documented until P5. Kind of like the incomprehensible "flaps" that appear at the bottom of the light parameters.

Open "ShaderNodes" ( "Shadernodes"?) on a spotlight.  I've never been able to find anything related to shaders for them, or any reason one would want RGB controls for "Flaps." And changing their colors is a baaaad idea. Try changing the PreviewLight to 0, but save first. They "do things," but what they do is pure madness. Not only are they still undocumented, but I couldn't even get an explanation of them from a egisys (pre-eFrontier) engineer. Ah, the mysteries of Poser....

M