The question I have is who kept the tape and knew how to find it? Who keeps recordings for a dozen years, just in case they enter politics?
Everything is digital now. It was probably just a computer file. The Bush guy probably spilled the beans on the interview and someone else in his circle with connections tracked down the tape. Senor-Brown fit the bill. Connections in both the Bush and NBC areas.
The story I heard was Billy Bush, newly hired by the Today show, blabbed about it while in Rio for the Olympics. It was others who searched and found the recording having learned of its existence.