A lot or a little?
Parents need to know that Note Rush: Music Reading Game is an app that helps budding musicians develop note-recognition skills. Kids complete a series of drills where they use their own instrument or a plugged-in MIDI keyboard to play notes displayed on screen. Drills can be timed or untimed, and people can create their own drills. The app doesn't require you to create an account and it doesn't have any built-in sharing features, though you can save drills you create to your device's camera roll and share them with other users like you'd usually share a photo. As of this review, the developer's privacy policy is very brief - just one sentence long - and it broadly indicates that anonymous usage data is collected, but there's no additional detail.