Constant DEFAULT_HEALTH_PROBE_INTERVAL 

pub const DEFAULT_HEALTH_PROBE_INTERVAL: Duration;

Default spec.health.probe.interval when unset: how often the backend health probe re-connects a Ready repository to confirm the kopia repository still exists at the backend. Conservative — a vanished/unreachable repository is rare and the probe runs a short mover Job — so it leans long. Part of the documented API contract, so it lives here, not in the controller.