This indicates whether a key synchronization session was configured by the user (manual) or created automatically by the system (auto). Distinguishing the two matters because auto-created sessions reflect dynamic peer discovery while manual ones represent deliberate administrator configuration that has to be maintained by hand. For example, an admin auditing key-sync sessions after a topology change would expect auto sessions to appear or disappear on their own, while a manual session toward a fixed data-center peer should persist until explicitly removed.