Location
Location is used to calculate prayer times on the iPhone. It is not sent to prayd. The calculation also works offline once the device has the required location and settings.
Selected apps
Apple's Family Controls picker represents selections with privacy-preserving tokens. As Apple explains in its Family Controls documentation, the picker lets users select apps and categories without revealing those choices to the app. prayd stores the tokens needed to apply shields, not a readable browsing profile.
Prayer history and pauses
Prayer logs, streaks, the make-up record and menstruation, travel or illness pauses stay on the device. They are not uploaded or sold.
Prayer-mat verification
The visual signature and comparisons are local. There is no server upload for mat images.
Deleting data
Delete the app to delete prayd's local data. Because there is no account or cloud copy, the history cannot be recovered afterwards. The formal details are in the privacy policy.