The system map

Every backend change starts with the same question: which screens render this, and what does this endpoint feed? The system map answers it by laying out views, API endpoints and data models as tiers, with the links between layers drawn in.

You pick a starting point and the map scopes itself around it. Endpoints that fan out to other APIs, internal or external, show up here too, wired card to card, since they have no screen to hang on.

Nothing on this map is a separate diagram you have to keep up to date. It is the same graph as the journey map, read from underneath.

And if neither built-in reading fits your question, a custom map is just a saved definition: a scope, a selection of species, a rendering mode. Not a new feature, a new angle.