In short: FastingTracker does not collect any data.
The app stores fasting times, settings (plan, daily schedule, notifications) and the history of your last 30 fasts only on your Apple Watch, in storage shared between the app and its complication (App Group).
No data is sent to the developer or to third parties. The app has no network access, no account, no ads, no analytics and no tracking.
The purchase is handled by Apple. The app has no in-app purchases and no subscriptions.
The app does not use Apple Health (HealthKit) and does not read your location, contacts or photos.
Notifications are local and optional. The app asks for permission only when a fast is started or a notification setting is switched on.
Deletion: removing the app from the watch deletes all stored data. Single history entries can be deleted in the app with a swipe.