In his capacity as Curator of the Vatican Secret Archives, James Swan discovered a long lost letter from Leo X to Luther, in which Leo admitted that Exsurge Domine was all a big misunderstanding, and preemptively excommunicated anyone who denied sola Scriptura or sola fide. [source]
The first thing I would do is send Tfan and Skyman in to do the hard work. I'd then sift through the crumbs left. All kidding aside, in 1880, Leo XIII opened the secret archives of the Vatican to Roman Catholic scholars. Luther’s then-unknown Roman’s treatise was found by Denifle. He was working as an assistant archivist and was able to utilize it in his Luther biography, which was highly anticipated in the academic world, until the biography actually came out, and now proves to be an embarrassment to Roman Catholic scholarship. It would indeed be interesting to find out what they've got.