Dan-Jessen
There's a system database for: contacts, text messages (SMS,MMS,RCS), and local calendar events (e.g. not google, cloud-stored calendar).
When you switch calendar apps or texting apps, the app will have all of your data. Easy switching.
There is no GOS calendar to open, view, and use. The GOS calendar app on the phone is simply the database.
Dan-Jessen what fitness data? Where would it even live?
I don't use this feature but I imagine it'd be stored in the health connect app