Rest assured. This app never sends your data to any external location, and we never store your data on our servers.
Your data is stored only on your device.
If you use the iCloud backup feature, the app communicates only with Apple's iCloud to back up or restore your data.
This means there is no risk of your data leaking. On the other hand, if you delete the app or your device breaks, we cannot restore the data in the app.
Please make your own backups regularly. Thank you.