In the movie Ronin (1998), I want to know what was in the case. I am well aware that the contents of the case are irrelevant to the plot - the Deniro character just wants to catch the IRA member, Seamus.
Just to summarize, the IRA and "the Russians" both want the case, and are willing to pay more than a $500,000 US for it. If it were biological weapons circa 1998, you'd think Russians wouldn't need to travel to western Europe and pay for it; they could get them on the cheap in Yeltsin's Russia.
Thus, I can't imagine what could be so valuable. It can't be a conventional weapon, as it isn't very heavy. It is to big to be just information. What could it be?
I'm looking for an in-universe answer.