web2c: Legalisms
Appendix A Legalisms
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In general, each file has its own copyright notice stating the copying
permissions for that file. Following is a summary.
The Stanford TeX programs and Web2c system itself are in the public
domain (<https://tug.org/texlive/copying.html>). The sources may be
copied verbatim, or used as the starting point of new software under
different names; however, per the wishes of the authors, they should be
modified only through a '.ch' file, but this is in the nature of a
development request rather than a legal requirement.
MLTeX, pdfTeX, LuaTeX, XeTeX, and all the other derived engines have
used various license terms for their additions to the base code, often
the GPL (see <https://www.gnu.org/licenses/#GPL>) or (for example) the
file 'web2c/pdftexdir/COPYINGv2'. They also mostly make use of
additional libraries with their own (compatible) terms. Please see each
program's sources.
The Kpathsea library is covered by the GNU Lesser General Public
License (⇒(kpathsea)Introduction). Therefore, the _binaries_
resulting from a standard Web2c compilation are also covered by the
LGPL; so if you (re)distribute the binaries, you must also (offer to)
distribute the complete source that went into those binaries. See
<https://gnu.org/licenses/#LGPL> or the file
'kpathsea/COPYING.LESSERv2'.