You can find the full text of the GPL in the plain-text file COPYING in the &xwp; installation directory. A formatted version of this document is available on the next page of this document.
By installing &xwp; on your system, you declare your agreement to the terms and conditions of the GNU General Public Licence, Version 2, as contained in the file COPYING in the &xwp; installation directory.
The GPL means more Legalese, but also more rights for you as a user and, if applicable, developer. The most obvious change is that &xwp;'s source code is also released.
The following brief explanations are intended as an introduction to the terms and conditions of the GPL only. They are not part of the licence agreement, for which only the terms and conditions in the COPYING file shall prevail.
Even though the source code is published, all developers retain the copyright to what they've written.
The GPL deals with these issues extensively. Before you use or modify any code parts of &xwp;, make sure you read the GPL thoroughly. If your software is GPL'd also, by all means feel free to use the code. If you have any questions, feel free to contact the developer's team.