The "Modify" panel lets you access various parameter values for PHXs. 

The Modify panel allow to set geometries properties like physical or rendering ones. Also, if the geometry allow it, you can attach embedded devices. In most case, devices are attached to geometries: for exemple motors are attached to joint's axes. 

General properties	Embedded devices	Shape
Modify geometries properties (Commons, Physics). If the geometry is a physics one, the Shape panel shows the 3D display of the this geometry.	Associate devices to the geometry. The allowed devices type is according to the geometry type.	Modify the geometries 3D display. (Render)

Manipulation panel