You can change the behaviour of scenes a bit with this parameter. Scene type can be set to 1 or 2, which overrides the default scene state. Scene state of 1 and 2 will only show the last video added to a group scene. Scene type 2 will mute the other videos, while scene type of 1 will not mute previously added videos.
This URL parameter option is a bit of a hack currently and may be replaced in the future.
This parameter is added to scene view links.