Indeed, in a better case the said "red line" is a part of the said bridge mapping; quite possibly even with anything that could be seen as a said line. Still, there's an inevitably implied point which, in a physical case, is the point where information enters some "optimization (and decision-making) routine"; even if it might not be clear where in the physical structures the said point is implemented in (which would be, again, a part of the bridge mapping).

Meta: I suspect we both need clearer ways to state these thoughts.