gimp/LICENSE

* The GIMP application core, and other portions of the official GIMP
  distribution not explicitly licensed otherwise, are licensed under
  the GNU GENERAL PUBLIC LICENSE -- see the 'COPYING' file in this
  directory for details.

[ The below explicit exemption, we hope, clears up the GIMP
  developers' position concerning an ambiguity with the GNU General
  Public License concerning what constitutes a 'mere aggregation'
  versus a combined or derived work.  The intention is to make it
  clear that arbitrarily-licensed programs such as GIMP plug-ins do
  not automatically assume the GNU General Public License (GPL)
  themselves simply because of their invocation of (or by) procedures
  implemented in GPL-licensed code, via libgimp or a similar interface
  to methods provided by the pdb: ]

* If you create a program which invokes (or provides) methods within
  (or for) the GPL GIMP application core through the medium of libgimp
  or another implementation of the 'procedural database' (pdb) serial
  protocol, then the GIMP developers' position is that this is a 'mere
  aggregation' of the program invoking the method and the program
  implementing the method as per section 2 of the GNU General Public
  License.

* 'libgimp' and the other GIMP libraries are licensed under the
  GNU LESSER GENERAL PUBLIC LICENSE -- see the 'COPYING' file in the
  libgimp directory for details.

* Icon themes are licensed under Creative Commons by-sa 3.0 or 4.0. See
  the 'COPYING' files in icons/Symbolic and icons/Color respectively.

* Any data used in artworks, such as brushes, patterns and the like, and more
  broadly likely all data inside the data/ folder should be under a CC0 license
  (Creative Commons Zero) or equivalent, i.e. "No rights Reserved", because GIMP
  contributors clearly don't intend to claim any right on anyone's work just
  because they used GIMP and its default data.
  We cannot clearly give proper licensing on all existing data, prior to the
  addition of this note in the LICENSE file (for historical reasons, simply
  because their contributors are since long gone), though we can say that an
  uncountable number of users have used these for dozens of years and never had
  legal problems as far as we know (it is anyway unclear whether anyone could
  really claim any right for very basic brush or pattern usage). Since 2015, we
  even have a clear FAQ entry to explicitly say the GIMP project has no
  intention whatsoever to put restrictions on people's work:
  https://www.gimp.org/docs/userfaq.html#can-i-use-gimp-commercially

  Therefore any new data file under the data/ folder will be expected to be CC0.
  All contributors are expected to read the LICENSE file and therefore are
  implicitly agreeing to license their data under CC0 by contributing it as core
  GIMP data.