Clause 7.1.3, titled pharmaceutical product specified substance identification, sits directly after the specified substance level. Its subject is the identification of that stratum as a whole rather than the parent substance route. The public contents give the title and the position but not the body. The detailed rule, including how the stratum is labelled and how a receiver tells a substance-stratum identifier from a specified-substance-stratum identifier, is not stated in the text we hold. The public material on the IDMP family describes the two strata as parallel constructions, each with four levels, and warns that the same product can have a different identifier in each. That is enough to state the practical point: the stratum is part of the identity of the identifier, not an optional label added afterwards.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.