The license terms under which R is distributed.
license()
licence()R is distributed under the terms of the GNU GENERAL PUBLIC LICENSE,
either Version 2, June 1991 or Version 3, June 2007. A copy of the
version 2 license is in file R_HOME/doc/COPYING
and can be viewed by RShowDoc("COPYING"). Version 3 of the
license can be displayed by RShowDoc("GPL-3").
A small number of files (some of the API header files) are distributed
under the LESSER GNU GENERAL PUBLIC LICENSE, version 2.1 or later. A
copy of this license is in file $R_SHARE_DIR/licenses/LGPL-2.1
and can be viewed by RShowDoc("LGPL-2.1"). Version 3 of the
license can be displayed by RShowDoc("LGPL-3").