All original CYTools code is open-source and is licensed under the GNU General Public License version 3.
Parts of the CYTools code are based on code snippets from the SageMath software package, and are redistributed under the GNU GPLv2+ license. These snippets are annotated clearly within the code. We also include a modified version of TOPCOM. The original TOPCOM code by Jörg Rambau and the patch based on a Debian package [src] by Doug Torrance are licensed under the GPLv2+ license. Further TOPCOM modifications are licensed under the GPL3 license.