This file makes two clues available, one each for Suspect: Kalkstein and Suspect:Leuvaarden, allowing them to be completed like all the other Suspect quests in Act II. It does so by replacing two clues obtainable from the Suspect Notes given to you by Raymond Maarloeve.  You will already have the one for Kalkstein (it can't be missed), and the one for Leuvaarden can be obtained by talking to the Mercenary Guards on the Dike.  If you've already started Suspect: Kalkstein and Suspect:Leuvaarden, just re-read the Suspect Notes and the new information will be added.

Drop the file in your Override folder in your The Witcher Enhanced Edition\Data directory (the actual game, not where the saves are). If you haven't got an Override folder, just make one.