Embodiments described herein relate to a software application that is configured to operate as an add-on software component to audio-playback software on a playback device of a media playback system. One embodiment may involve displaying, on a user interface of a controller of a media playback system, a zone identifier that identifies a zone of the media playback system, where the zone comprises a playback device that has audio-playback software installed thereon; and displaying, on the user interface of the controller, an application identifier in association with the zone identifier, where the application identifier indicates that a software application installed on the playback device is configured to operate as an add-on software component to the audio-playback software.