_block_template_add_skip_link( string $template_html ): string

350function _block_template_add_skip_link( string $template_html ): string {351	// Anonymous subclass of WP_HTML_Tag_Processor to access protected bookmark spans.352	$processor = new class( $template_html ) extends WP_HTML_Tag_Processor {353		/**354		 * Inserts text before the current token.355		 *356		 * @param string $text Text to insert.357		 */358		public function insert_before( string $text ) {359			$this->set_bookmark( 'here' );360			$this->lexical_updates[] = new WP_HTML_Text_Replacement( $this->bookmarks['here']->start, 0, $text );361		}362	};363 364	// Find and bookmark the first DIV.wp-site-blocks.365	if (366		! $processor->next_tag(367			array(368				'tag_name'   => 'DIV',369				'class_name' => 'wp-site-blocks',370			)371		)372	) {373		return $template_html;374	}375	$processor->set_bookmark( 'skip_link_insertion_point' );376 377	// Ensure the MAIN element has an ID.378	if ( ! $processor->next_tag( 'MAIN' ) ) {379		return $template_html;380	}381 382	$skip_link_target_id = $processor->get_attribute( 'id' );383	if ( ! is_string( $skip_link_target_id ) || '' === $skip_link_target_id ) {384		$skip_link_target_id = 'wp--skip-link--target';385		$processor->set_attribute( 'id', $skip_link_target_id );386	}387 388	// Seek back to the bookmarked insertion point.389	$processor->seek( 'skip_link_insertion_point' );390 391	$skip_link = sprintf(392		'<a class="skip-link screen-reader-text" id="wp-skip-link" href="%s">%s</a>',393		esc_url( '#' . $skip_link_target_id ),394		/* translators: Hidden accessibility text. */395		esc_html__( 'Skip to content' )396	);397	$processor->insert_before( $skip_link );398 399	return $processor->get_updated_html();400}