We're happy to help with DefiLlama, the personal subscription tracker.
Where is my data stored? On your device only. There are no accounts and nothing is uploaded to us.
How do I remove the example subscriptions? Open Settings and tap "Clear example data".
What does the sparkle button do? If you enable Cloud AI in Settings, it rewrites the note you're editing to read more clearly. It is optional and off by default.
How do I delete everything? Settings → "Delete all subscriptions".