A session token identifies the state of settings visible to clients. It changes when the settings have been modified by this service, due to user profile switching, factory reset or other reasons that are not caused by setting owning services.

Clients must observe the session token and use it to modify settings. The session token is not needed to read settings but clients have to re-read settings when the session token changes.

The session token ensures that settings are modified for the right session, preventing accidentally overwriting another user's setting when the user profile is switched, or accidentally having a non-default value after a factory reset.

Note: Clients should not retry a modification of a user profile-specific setting if it fails due to invalid token, which may happen due to user profile switching.