What is the file format of Here Maps on N9? Can these files be read with other applications than N9 Maps/Drive? Are the files encrypted some way?

I was thinking if it would be possible to use the N9 to download the map files and then transfer them to Jolla for offline use (OK, this would probably violate the license terms of N9 maps and there is also no application for Jolla to open the files but let's not go there yet...).