This software is copyright and you are explicitly granted a license which gives you, the “user” of the software, legal permission to copy, distribute and/or modify the software.
Note. This license applies when the author has adopted the ‘Clarified’ or 2.0 version of the license, and therefore counts as a free license. (Packages licensed under version 2.0 may be included in any TeX distribution, by contrast with those licensed under the original Artistic license.
Further information about this type of license is available from the Perl Web page and general information is available about other TeX Catalogue Licenses.