I mean we know what the binary layout is of things, so I never understood (outside of the time that it would take to build such a utility) why I've never been able to find something that says, "Oh yeah, that binary string contains three doubles, separated by a NULL character, with an int, followed by a UTF-8 compatible string."
Such a tool would be incredibly useful for reverse engineering proprietary formats, and yet I don't know of a good one, so if it exists it's at least obscure enough for it to have escaped my knowledge for well over a decade.