drc Directory Reference

Files
	connectivity.hpp
	Copper connectivity with KiCad's semantics, shared by the DRC (unconnected/dangling checks) and the router (which pads are already joined).
	copper.hpp
	Copper items with exact shapes, built from the board model, for DRC and routing obstacles.
	coupling.hpp
	Coupled segments of a differential pair, as KiCad 10.0.6's diff-pair coupling test finds them (pcbnew/drc/drc_test_provider_diff_pair_coupling.cpp, doc 05 §59): a track of the P net and one of the N net on the same layer are coupled where they run on parallel, distinct lines and their projections overlap.
	drc.hpp
	Design-rule checker equivalent to KiCad's for routing-relevant rules (design doc 03 §6).
	length.hpp
	Net length and propagation delay as KiCad 10.0.6 measures them for its length and skew checks (design doc 05 §59; KiCad's LENGTH_DELAY_CALCULATION with the DRC's options: via spans, merged tracks, tracks clipped in pads).
	refill.hpp
	Zone refill in the engine (doc 05 §36): the fills KiCad 10's zone filler would draw for the board's current copper, so connectivity can be judged as kicad-cli pcb drc --refill-zones judges it.
	rule_engine.hpp
	Resolves KiCad constraints for pairs of copper items (design doc 03 §6): net-class clearances, local pad overrides, board minimums and custom .kicad_dru rules with their conditions.
	rule_geometry.hpp
	Positional custom-rule predicates.