AppSelector is a T-Mobile feature that gives you control over the apps that are installed on your phone during the first boot process. You can safely remove AppSelector using the standard Android app removal process, but T-Mobile can add it back to your phone later via an update.
How to Remove or Uninstall Hidden Apps / Remove Spy Apps from Your Phone
AppSelector is an app that comes pre-installed on new T-Mobile phones. When you first set up your T-Mobile device or after you factory reset a T-Mobile device, AppSelector lets you select and install other applications that you might find useful.
Apps are automatically suggested based on your phone usage. This means that you must agree to send usage data to the app developer for the feature to work.
This feature is useful for users who don’t know what apps they need, as it automatically suggests apps you might need based on phone usage and a questionnaire. However, it can cause problems on phones that don’t have much storage space; in some cases, it might install apps you don’t want.