It was a Vulcan memory crystal.It just seems like a very peculiar thing to be in the data, especially when you have to work under the assumption that the entire thing was kept very secret in order for the universe to unfold the same way. Also, why would that quantum signature even be a big deal a century later that it would be included in a Klingon memory core?
A lot of tap dancing has to be done...![]()
Remember T'Pol stole the data.