In the scene select the game object that the camera to link with the Physical Camera and add component "Camera/Physical Camera"
Alternatively, you can drag and drop an existing physical camera prefab onto a camera object.
Notes
Many of the fields, at the moment, have no impact in Unity itself.
Should work with Unity 5.6 and up.
Work in progress.
For the Physical-Camera to synch with a camera, it's needs to be explicitely linked throught it's "Associated Camera" property. This property is auto-set, when not set, to the first camera object that it find on it's parent game object.