D5 was in red ink on the top of a decent declass doc back when. Multiple meanings exist and from Skipper saying “they thought it meant Sate Funeral” means to me it was a deliberate misdirection for the enemy while documenting “future proves past” protocol (and to drive them nuts: they attempt decodes more than anons). Keep in mind, multiple meanings exist. In this case it seems, based on anons research, it may have many meanings. Like D5 is an avalanche measure meaning the biggest one. Also the “D5” dirty governors … yada yada yada