PBR inside the SDK :
The small reflective sphere in the center is a LightProbe.
That's a new type of Light (on the PBRIsComing branch only) that is used for environment lighting.
It has a position, and a bounding volume (for now only bounding sphere is supported)
Here you can see the gizmo in the SDK with a smaller radius :
Note how the radius influence the lighting.
There is still a huge amount of work to do for propper PBR support, but I though I'd give some heads up.