The PCBU ensures that a licence holder supervising a trainee doing high risk work provides direct supervision (directing, demonstrating, monitoring and checking the work according to the trainee's competence, with capacity to respond in an emergency), unless the task makes direct supervision impracticable or unnecessary and reduced supervision will not put anyone's health or safety at risk.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.