$CAMERA is a system node which is implemented in the _CameraClassMethods script, and is used to communicate camera changes to the appropriate server, to store data in a user's _PlayerAccount node about the current camera status.
The associated script holds the following three callback methods:
_OnCameraAdd() _OnCameraRemove() _OnCameraActivate()
These methods will in turn call appropriately named override methods if implemented on the system node.
HeroEngine makes use of the _OnCameraActivate() method callback to transmit camera changes to the server, for storage on the user's _PlayerAccount node in the _currentCamera field. This allows tools and systems to more easily handle special situations that require manipulation of the camera. For example, Hero's Journey's /GO mechanics for traveling to a character checks for whether the /GOing player's _currentCamera is the "FLY" camera when /GOing to a character in the same area/instance. If so, the mechanic repositions that camera along with teleporting the character.