Many of the files have this attached:

AUTHOR AND COPYRIGHT
Copyright (c) 1997, 1998 Tom Christiansen All rights reserved.
 
When included as part of the Standard Version of Perl, or as
part of its complete documentation whether printed or
otherwise, this work may be distributed only under the terms
of Perl's Artistic License.  Any distribution of this file
or derivatives thereof outside of that package require that
special arrangements be made with copyright holder.
 
Irrespective of its distribution, all code examples in this
file are hereby placed into the public domain.  You are
permitted and encouraged to use this code in your own
programs for fun or for profit as you see fit.  A simple
comment in the code giving credit would be courteous but is
not required.