Note that in all cases of "EE<lt>whateverE<gt>", I<whatever> (whether
an htmlname, or a number in any base) must consist only of
-alphanumeric characters -- that is, I<whatever> must watch
+alphanumeric characters -- that is, I<whatever> must match
C<m/\A\w+\z/>. So S<"EE<lt> 0 1 2 3 E<gt>"> is invalid, because
it contains spaces, which aren't alphanumeric characters. This
presumably does not I<need> special treatment by a Pod processor;