XBMCXbox software is just like XBMC licensed under the GNU General Public License (GPL) by its developers, meaning they allow anybody to redistribute XBMCXbox source code under very liberal conditions. However, in order to compile the Xbox build of XBMCXbox into executable form, it is currently necessary to use Microsoft's proprietary XDK (Xbox Development Kit) which is only available to licensed developers and the resulting code may only be legally distributed by Microsoft. Accordingly, code compiled with an unauthorized copy of the Xbox Development Kit may not be legally distributed by anyone other than Microsoft.