This distrubition bundles a smattering of files produced by other entities for the sake of testing.

While these libraries are not used for their author-created exectuble content,
and are never loaded into memory, ( they're only used for structure purposes ),
they are, still, nonetheless, bundled and distributed code.

The respective copies of the various terms of licensing can be found in LICENSES

Files: t/test_files/libz.so, t/test_files/libz.so.1.2.3.debug
Copyright: 1995-2005, Jean-loup Gailly <jloup@gzip.org>
 1995-2005, Mark Adler <madler@alumni.caltech.edu>
License: zlib

Files: t/test_files/libreadline.so.6.0.debug
Copyright: 1987-2009, Free Software Foundation, Inc.
License: GPL-3

Files: t/test_files/libc.so.6
Copyright: 1991-2008, Free Software Foundation, Inc.
License: LGPL-2.1+