Bus factor zero

The state of a system nobody has ever understood, including its author, reached when generation outruns comprehension. One worse than the classic bus factor of one, because the remedies for that case (pairing, review, documentation, onboarding) all assume an understanding exists somewhere to be distributed. Knowledge lost can be excavated; knowledge never formed leaves nothing to excavate, so load-bearing and accidental become indistinguishable and the system freezes.