Yes, it is a bit confusing:I've added these apart from GeoGebra - I'm not sure on it's licensing or where to get the source. It says source code is GPL but there is a non-commercial use license that is quite prominent. It does look quite cool though.
We license the different component parts of GeoGebra differently depending on their origin (authorship) and depending on your intended use of GeoGebra (see also next question)
Thus, there are really many different licenses involved in the background.
- the source code is licensed under the GNU General Public License to ensure consistency with the various other pieces of software and libraries which are used within the GeoGebra source code (for a complete list of which see: https://wiki.geogebra.org/en/Reference:Sources_For_Used_Libraries).
- the GeoGebra installers (for various platforms including Linux, Mac OS, Windows, Android, iOS) and our web services (including GeoGebra Materials platform) are made available under our own licensing terms which have been drafted by an experienced law firm. We allow you to use the installers and web services for non-commercial purposes only provided you acknowledge GeoGebra; and
- the GeoGebra language files are made available under a Creative Commons license, which allows non-commercial use of these files.