We respect your privacy. For that reason, Music Tracker doesn't use your data or try and gain information about you via analytics. By default, nothing ever leaves your device. If you enable push notifications, we will be given a unique identifier from Apple (unlinkable to you) that will allow us to send you push notifications. No information about your device, music library, or any personal information is ever sent back to us and all processing of your library is done on your device.
With regards to push notifications, we use these to send you a morning summary notification if anything changed the day before i.e. "1 track added, 4 changed, and 0 deleted". We will never use push notifications for marketing, spamming, or any other nonsense and we only send the summary once per day if something changed on the previous day. We never display anything on the app icon.
Music Tracker contains no advertising, tracking, analytics, or in-app purchases.
Beyond the fact that we do not want any of your information, we've also submitted a bug report to Apple (rdar://24168798) pointing out that access to the music library does not require user permission (like calendars, contacts, location, and photos do) but definitely should as currently a nefarious developer can access your library without your knowledge. Whilst having a permission dialogue would add a bit more complexity to this app, it is our belief that privacy should be more important. Hopefully this will be addressed by Apple in a future version of iOS.