What license is Joomla! released under?
From Joomla! Documentation
Joomla! is released under the GPL (Gnu General Public License 2). Details of the GPL can be found here: http://www.gnu.org/licenses/gpl.html.
Joomla! is released under the GPL (Gnu General Public License 2). Details of the GPL can be found here: http://www.gnu.org/licenses/gpl.html.