How can I detect when the users open and closes Oculus Home?

I would like to detect whether the users open Oculus Home such that I can allow my game to pause itself.

Unity automatically does this for you. They are working on re-enabling the "Run in Background" checkbox, but it currently has no effect and the app always pauses when Home or another app is focused. You can detect focus changes by subscribing to OVRManager.VrFocusAcquired/Lost. In general, you should not be directly using the internal OVRPlugin class. All functionality is exposed through the supported public classes such as OVRManager, OVRCameraRig, OVRDisplay, OVRTracker, and OVRInput.