This means that each different run of Perl will have a different
ordering of the results of keys(), values(), and each().
-See L<perlsec/"Algorithmic Complexity Attacks"> for more information.
+See L<perlsec/"Algorithmic Complexity Attacks"> for more information,
+and also L</PERL_HASH_SEED>.
=item PERL_HASH_SEED_DEBUG
(Since Perl 5.8.1.) Set to "1" to display (to STDERR) the value of
the hash seed at the beginning of execution.
+See also hash_seed() of L<Hash::Util>.
=item PERL_ROOT (specific to the VMS port)