NSBluetoothAlwaysUsageDescription Allow Bluetooth to send context updates to Glass. NSCalendarsUsageDescription Allow calendar access to show upcoming events on Glass. NSCalendarsFullAccessUsageDescription Allow full calendar access to show upcoming events on Glass. NSAppleMusicUsageDescription Allow access to your Now Playing information to show music on Glass. NSLocationWhenInUseUsageDescription Allow location access to compute context cards for Glass. NSLocationAlwaysAndWhenInUseUsageDescription Allow background location access to keep Glass context updated while moving. UIBackgroundModes bluetooth-peripheral bluetooth-central location