A general clause in this series does the same work Part 2's clause 5.1 does: it names the mechanism family, points to the clauses that carry the parameters and the process, and says what the annexes are for. For a reader, it is the place to confirm that the rest of the document is about the mechanism family you think it is about.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.