`parse_text`

     if ( /^([A-Z])<([^<>]*)>$/ ) {
         $seq = Pod::InteriorSequence->new(
                    -name   => $1,
                    -ldelim => "<",  -rdelim => ">",
                    -file   => $file,    -line   => $line
                );
         $seq->append($2);
         $seq->nested($seq_stack[-1]) if @seq_stack > 1;
         $seq_stack[-1]->append($expand_seq
                                ? &$xseq_sub($self, $seq)
                                : $seq);
     }

What was this about?
We're building a tree of Pod::InteriorSequence nodes
- In X<Y<...>>, node Y is a child of node X
- The ->nested call installs a pointer to X into Y