npub1cl…a3zny on Nostr: Looks interesting but I'm not on mac or Ios- does it work like contrine on android, ...

Looks interesting but I'm not on mac or Ios- does it work like contrine on android, serving as a local backup that you can then export to relays if and when you want to, or does it work as a public server so people pulling your notes and media are pulling them literally from your phone?