Analysis panel
The Analysis switch in Photo Lighting describes your current setup in familiar lighting terms, so what you see in the 3D view gets a name and a number.
It shows the estimated Key:Fill ratio, the likely lighting pattern, the Kelvin difference between lights, relative light levels in stops, the falloff and an overall description of the contrast. Only lights that are switched on count.
Want to change what it reads? Adjust the light controls, or use Photo Tools to isolate a light or set a quick Key:Fill ratio.