According to the source, Karr wrote about a check stub on John Ramsey's desk in the amount of $118,000, specifics about a staircase in the Ramsey’s home and details about the basement where JonBenet was killed.
http://www.cbsnews.com/stories/2006/08/18/national/main1909118.shtml
(this one is dated from the 18th)
Don't know what the specifics of the staircase might be, so I can't comment. It was winding, it had fake Christmas greenery wrapped around the hand railing, it was the back way from the upper floor where the master bedroom was, it was where Patsy claimed to have found the ransom note a few steps up from the bottom.
There are other things that have been common knowledge among case followers for all these many years, so I can't conjure up which of many he might have told Tracey about. Most of it has even been on TV.