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 invokation 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.