function jetpack_sitemap_uri( $filename = 'sitemap.xml' ) {
  global $wp_rewrite;

  $location = Jetpack_Options::get_option_and_ensure_autoload( 'jetpack_sitemap_location', '' );

  if ( $wp_rewrite->using_index_permalinks() ) {
    $sitemap_url = home_url( '/index.php' . $location . '/' . $filename );
  } elseif ( $wp_rewrite->using_permalinks() ) {
    $sitemap_url = home_url( $location . '/' . $filename );
  } else {
    $sitemap_url = home_url( $location . '/?jetpack-sitemap=' . $filename );
  }

  
/**
 * Filter sitemap URL relative to home URL.
 *
 * @module sitemaps
 *
 * @since 3.9.0
 *
 * @param string $sitemap_url Sitemap URL.
 */
  return apply_filters( 'jetpack_sitemap_location', $sitemap_url );
}