Neither the app and the website has any telemetry or tracking, so no user identifiable information is collected. All data the user enters in the app is stored locally on the device or sent to Apple's services to update items on the user's developer account at Apple.
The app uses RevenueCat to facilitate the in-app purchases and handling subscriptions. When a subscription is started, RevenueCat is notified. The information sent to RevenueCat is anonymous.
In the app some security measures has been implemented to protect the user's information. For the app to communicate with Apple's services an API Key is needed. The API Key, generated on App Store Connect by the user, is stored in the Keychain of the device runnning the app. The API Key can only be read from the Keychain by the AppDab app.