FrogReaver
The most respectful and polite poster ever
You are taking me way too literally. I was using clue as an analogy. But the point is what is contained in the envelope is a real mystery you can solve by opening the envelope. It would be a much different game if that info were rolled on a table at the end or players decided what was in there. Again this isn’t a crazy idea that the players in a game where the GM determines the details of the mystery before hand are really solving a mystery in this approach and that that can matter for agency. Also that takes nothing away from the approaches you are talking about (it is just acknowledging a difference between them)
It’s so different I would hesitate to call them by the same name. One is more like emulating the fiction of solving a mystery. The other is emulating the actual solving of a mystery.
Both methods are going to produce fiction of a mystery being solved, but only one actually was solved by the players.