New Smart Objects options ?

I can't find any information on the definitions of the new smart object options in cc2014 ?

Layer comps in smart objects

Consider a document with layer comps placed as a smartobject within another document. When you select the smartobject in the containing document, the Properties panel gives you access to the layer comps that were defined in the source file.

This feature lets you change the state of the smartobject at a layer level without editing the smartobject

.