code: protected function add_category_links()
      {
          $cat_id = \absint(\get_query_var('cat'));
          $cat = \get_category($cat_id);
          $cat_parent_id = \absint($cat->parent);
  
          $cat_links = [];
  
          if ($cat_parent_id) {
              while ($cat_parent_id) {
                  $cat_parent = \get_category($cat_parent_id);
                  $cat_links[] = $this->makeLink(
                      $cat_parent->name,
                      \get_category_link(\absint($cat_parent->term_id))
                  );
                  $cat_parent_id = \absint($cat_parent->parent);
              }
  
              $this->links = \array_merge(
                  $this->links,
                  \array_reverse($cat_links)
              );
          }
  
          $this->links[] = $this->currentLink(
              $cat->name,
              \get_category_link($cat_id)
          );
      }
docs: Called if $page === 'category'