: Keeping a "hidden" local backup on the device that isn't synced to a cloud service for extra privacy.

: The user-hidden tag often refers to features that allow the app to operate discreetly or store backups in a secure, hidden partition within the app to prevent unauthorized access to your contact data.

: The "Pro" designation typically indicates a version that allows for full, unlimited exports of your entire address book without the restrictions found in "Lite" versions.

When dealing with .ipa files from unofficial sources, always ensure you are using a trusted sideloading method. Handling contact data involves sensitive personal information, so verify the app's permissions once installed. If you'd like, I can help you with: Sideloading instructions for iOS 14+ Alternative official apps for contact management

This specific file string——appears to be a direct download link or a specific build identifier for a mobile application package (IPA) used on iOS devices.