Blackbox for Windows is free software, released under the GNU General Public License (GPL), with an extension that allows linking of proprietary modules under a controlled interface. What this means is that plugins etc. are allowed to be released under any license the author wishes. Please note, however, that the original Blackbox gradient math code used in Blackbox for Windows is available under the BSD license.

Any user who uses this codebase for modifications other than to the main shell code is hereby kindly asked not to create unsolicited forks of the code. Please respect the work of the authors and send your modifications to the Blackbox for Windows Development Team prior to release for analysis. If deemed valuable the modifications be added to the main codebase, and you will of course receive full credit for your work. If you still want to create your own fork or other software based on the work of the Blackbox for Windows Development Team the origin of this software must not be misrepresented; you must not claim that you wrote the original software.
And remember, the polite thing to do is to contact us prior to release, even if it's just to let us know about it.

Thank you for your cooperation. Enjoy! :D