I finally got around to book my (train) trip back from Zagreb. The hotline of Deutsche Bahn was… interesting. The booking system crashed and I was called back. But in the end it worked and I can print it the next time I get near a vending machine.
I'm worried how I manage to get there from Banja Luka on my own. And the travel to Zagreb together with Joachim Breitner won't be as comfortable as it should be. But meh, I'm going to DebConf again! \o/