Credibility is the first principle in the set. The subject is the credibility of a statement: a reader has to be able to believe it, and the programme has to be able to show why. In practice that means the statement rests on a method, a record and a responsible party rather than on assertion. The rationale subclause is where the standard explains what makes a statement credible, and it should be read with the principle.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.