The developer does not collect any data from iStyr. The app has no account, analytics, advertising, or tracking.
If you allow location access, iStyr uses your location to show you on the map. The developer does not receive your location. You can turn off location access in your device settings. Apple provides the map; see Apple's Privacy Policy.
iStyr gets station data from Nextbike, which may receive your IP address when serving the request. Your location and preferences are not sent to Nextbike. Favorites and sorting preferences stay on your device. You can remove favorites in the app or clear all preferences by deleting the app's stored data. The developer has no app data to delete.