vtlib/vtlib-Copyright.txt
vtlib uses third party libraries to enable certain functionality.
1. For creating and unpacking zip files
-- ====================================
vtlib/thirdparty/Dzip.php
vtlib/thirdparty/dUnzip2.inc.php
DOWNLOAD URL:
http://www.phpclasses.org/browse/package/2495/
BSD License: http://www.opensource.org/licenses/bsd-license.html
NOTE: Bug Fix was added to function addFile of dZip class.