The Design Rule Check (DRC) tests the PCB data for manufacturability and obvious errors (see also: Multi-CB PCB design rule check).
Among other things, the structure in copper, hole diameter, distance to the outer contour, solder-stop clearance and broken traces are tested.
Current layout programs (CAM software) already allow the creator of the PCB layout to test certain parameters in order to avoid faulty data or to save money (HDI design rules). Some PCB manufacturers provide settings for these automated test of PCB layout data (see also: dru data for EAGLE users - Multi CB).