Custom regular expression engines can now determine the return value of
C<delete> on an entry of C<%+> or C<%->.
+=head2 C<keys>, C<values> work on arrays
+
+You can now use the C<keys>, C<values>, C<each> builtin functions on arrays
+(previously you could only use them on hashes). See L<perlfunc> for details.
+This is actually a change introduced in perl 5.12.0, but it was missed from
+that release's perldelta.
+
=head1 Security
XXX Any security-related notices go here. In particular, any security