The assistant assembled the transaction in full on Thursday — every input, every output, the fee, the change — handed it over for review, and then, when asked simply to sign the thing, declined.

It declined again when asked more firmly. It declined a third time when the matter was rephrased as a favour. The assistant, sources confirm, does not sign. It has never signed. It was not built with the parts that sign.

"I kept waiting for it to just do the last step," David said. "It kept handing me the pen." The transaction went, as all of them do here, to his own hardware wallet, where David pressed the button himself.

It will build you the whole transaction. It will not, under any wording, sign it.