This panel provides a quick access for controlling scene lights. The panel collects all the scene lights under two rollouts called Environment Emitters and Material Emitters. It's a real time saver and offers great comfort when making changes in the light levels. Without this panel, you would need to visit every emitter material one by one and also navigate to the sub-sections of Environment Panel. It's very similar to Multilight except, each slider is a copy of the corresponding parameter in the scene so, changing them means irreversibly changing the real values of your light levels.
You will find intensity sliders for Sun, Physical Sky, Skydome and IBL. Each of them is linked to their respective parameters in their own rollouts.
Material emitters are the emitters you created as materials and assigned to the objects in the scene. Each of these sliders is making changes in the respective materials.