src/lib/Breadcrumbs.php
protected function add_tag_links()
    {
        $tag_id = \get_query_var('tag_id');
        $tag_label = (\single_tag_title('', false) ?: '');

        $this->links[] = $this->currentLink($tag_label, \get_tag_link($tag_id));
    }
protected function add_tag_links()
    {
        $tag_id = \get_query_var('tag_id');
        $tag_label = (\single_tag_title('', false) ?: '');

        $this->links[] = $this->currentLink($tag_label, \get_tag_link($tag_id));
    }
Called if $page === 'tag'