The script files under the Demos sub-directory are under public domain license; you are free to adjust them to your needs and distribute the modified scripts.
The Matlab/Octave version of WavePacket, consisting of the source code files in the Source sub-directory, is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 3 as published by the Free Software Foundation.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
As a special exception to the GPL, the copyright holders give you permission to distribute the WavePacket program without supplying the Matlab interpreter and libraries required to run this program. You are furthermore allowed to compile and link the program with the Matlab built-in compiler, and distribute the resulting executable together with the required Matlab runtime libraries, following the terms of the GNU GPL for the WavePacket code, and the Matlab license for the runtime libraries.