A failure mode may be excluded as incredible only for components with inherent physical properties (for example a suitably designed transformer, relay or resistor cannot fail into a particular mode), by the procedure that justifies the exclusion from the physical property, the component's construction and the operating and environmental conditions; the exclusion is documented and used where inherent fail-safety is claimed.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.