One of the most underrated features that is built in Android 4.3 is the ability to grant permissions to apps. The feature is called App Ops. App Ops displays various permissions that are granted to different apps, according to Android Police. The feature shows what apps know your location, has the ability to read your calendar, and the ability to access your contacts. In most cases, you would want apps like Gmail to be able to access your contacts, but then there may be some apps that you do not want grabbing content from your phone. You can adjust the permissions within App Ops. Android 4.3 users will be able to download another app from Google Play called Permission Manager. This app gives you direct access to the permission settings.