The manufacturer applies a documented firmware quality control process covering development, testing, release and revision of IED firmware, so that firmware updates are controlled, authenticated and traceable, and the IED accepts only firmware that passes its integrity checks (2013's 5.7 firmware quality control, carried into 5.7, working with the integrity requirements of 5.3).
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.