The B2C extension: the overlay that reads and writes the four terms of model/b2c/0.1.json through the paths of the core model, and the gross authoring policies over it. The overlay sources are generated from the extension registry by esj-generator and are checked in; the core API stays the core API. The policies are hand-written and derive the net core terms from the gross figures a consumer was shown, with the arithmetic of EN 16931-1 and one report per run.