The tubelib2 mod for Minetest is

Copyright (C) 2017-2018 Joachim Stolberg  

License of source code
----------------------

This mod is free software; you can redistribute and/or
modify it under the terms of the GNU Lesser General Public License version 2.1 or later
published by the Free Software Foundation.

This mod 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this mod; if not, write to the
Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
Boston, MA  02110-1301, USA.


License of media (textures, sounds and documentation)
-----------------------------------------------------

All textures, sounds and documentation files are licensed under the
Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)
http://creativecommons.org/licenses/by-sa/3.0/