=item * Unknown command "I<CMD>"
An invalid POD command has been found. Valid are C<=head1>, C<=head2>,
-C<=over>, C<=item>, C<=back>, C<=begin>, C<=end>, C<=for>, C<=pod>,
-C<=cut>
+C<=head3>, C<=head4>, C<=over>, C<=item>, C<=back>, C<=begin>, C<=end>,
+C<=for>, C<=pod>, C<=cut>
=item * Unknown interior-sequence "I<SEQ>"
'cut' => 1,
'head1' => 1,
'head2' => 1,
+ 'head3' => 1,
+ 'head4' => 1,
'over' => 1,
'back' => 1,
'item' => 1,