Relay uses a username flow so bookmark sync does not need an email identity as its foundation.
What Relay asks for instead
The passkey is the normal login. The Recovery Kit unlocks the encrypted vault locally if every passkey is unavailable.
The extension needs bookmark access to read, compare, preserve folders, and apply changes in the browser.
Relay keeps local browser identity, session state, plan cache, and sync metadata in browser storage.
Compare the tradeoff: Read the privacy policy or install Relay.