This is Debian GNU/Linux's prepackaged version of HTML::TagSet. This is a perl modules which provides data tables useful when dealing with HTML. It is currently maintained by Debian Perl Group, previously by Kenneth J. Pronovici , and was originally packaged by Michael Alan Dorman . The original sources should always be available from the Comprehensive Perl Archive Network (CPAN): http://search.cpan.org/dist/HTML-Tagset/ The HTML::Tree copright is as follows: Copyright 1995-2000 Gisle Aas. Copyright 2000-2005 Sean M. Burke. Copyright 2005-2008 Andy Lester. This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. Perl is distributed under your choice of the GNU General Public License or the Artistic License. On Debian GNU/Linux systems, the complete text of the GNU General Public License can be found in `/usr/share/common-licenses/GPL' and the Artistic Licence in `/usr/share/common-licenses/Artistic'.