Every account has a computed, owner-only tech space holding the space list, devices, profile and settings; it syncs by the same rules and a new device pulls it first.

It is how multi-device works with no server that can read your devices.

Every account has one more space. Private, and owner-only. The tech space.

Its id is computed from the account's public key. Every device of the account finds it without asking anyone.

It holds everything that is about the account, not about a shared space. The list of spaces you are in. Your devices. Your profile. Your settings.

Its guest list has one member, and the network refuses any further slip. There is no such thing as a shared account.

Restore a new phone from your phrase. It computes this space, pulls it first, and immediately knows every space to join.

It syncs by the same rules as everything else. There is no separate preferences sync, and no server that can read which devices are yours.

Check yourself. What does a freshly restored phone pull first, and why?