Suppose there are three sealed black boxes with locks which are impossible to open. We are not allowed to investigate them (poke them, weigh them or interrogate them in any way).
We are told that no one can EVER open Box 1 now or at any time in the future. There is no history of it. No one knows or will ever know what it contains.
Someone has placed something in Box 2 and died, telling no one and leaving no record of its contents.
Box 3 has a time-lock mechanism so that at some time in the future it will spring open and reveal its contents.
So in Box 1 we cannot know its contents, nobody has ever known its contents and nobody will ever know its contents.
In Box 2 someone once knew its contents but we don't know its contents now and nobody in the future will ever know its contents.
In Box 3 someone once knew its contents, we don't know its contents now, but somebody in the future will know its contents.
Q. Is it reasonable to ask the question "What is in the box?"?
A. 1 No; 2 Maybe; 3 Yes.