Website:
https://www.gaia-gis.it/fossil/libreatlas

So to get started, you simply:

1. Install the LibreAtlas application 
2. Download or copy a LibreAtlas database of your choice (available at
   http://www.gaia-gis.it/gaia-sins/libreatlas-resources/) and unpack to the
   directory of your choice 
3. When starting the application for the first time,
   you open the LibreAtlas database ...and that's absolutely all!