public function is_staging_site() {
    // Core's wp_get_environment_type allows for a few specific options. We should default to bowing out gracefully for anything other than production or local.
    $is_staging = ! in_array( \wp_get_environment_type(), array( 'production', 'local' ), true );

    $known_staging = array(
      'urls'      => array(
        '#\.staging\.wpengine\.com$#i', // WP Engine.
        '#\.staging\.kinsta\.com$#i',   // Kinsta.com.
        '#\.kinsta\.cloud$#i',          // Kinsta.com.
        '#\.stage\.site$#i',            // DreamPress.
        '#\.newspackstaging\.com$#i',   // Newspack.
        '#\.pantheonsite\.io$#i',       // Pantheon.
        '#\.flywheelsites\.com$#i',     // Flywheel.
        '#\.flywheelstaging\.com$#i',   // Flywheel.
        '#\.cloudwaysapps\.com$#i',     // Cloudways.
        '#\.azurewebsites\.net$#i',     // Azure.
        '#\.wpserveur\.net$#i',         // WPServeur.
        '#\-liquidwebsites\.com$#i',    // Liquidweb.
      ),
      'constants' => array(
        'IS_WPE_SNAPSHOT',      // WP Engine.
        'KINSTA_DEV_ENV',       // Kinsta.com.
        'WPSTAGECOACH_STAGING', // WP Stagecoach.
        'JETPACK_STAGING_MODE', // Generic.
        'WP_LOCAL_DEV',         // Generic.
      ),
    );
    
/**
 * Filters the flags of known staging sites.
 *
 * @since 3.9.0
 *
 * @param array $known_staging {
 *     An array of arrays that each are used to check if the current site is staging.
 *     @type array $urls      URLs of staging sites in regex to check against site_url.
 *     @type array $constants PHP constants of known staging/developement environments.
 *  }
 */
    $known_staging = apply_filters( 'jetpack_known_staging', $known_staging );

    if ( isset( $known_staging['urls'] ) ) {
      foreach ( $known_staging['urls'] as $url ) {
        if ( preg_match( $url, wp_parse_url( site_url(), PHP_URL_HOST ) ) ) {
          $is_staging = true;
          break;
        }
      }
    }

    if ( isset( $known_staging['constants'] ) ) {
      foreach ( $known_staging['constants'] as $constant ) {
        if ( defined( $constant ) && constant( $constant ) ) {
          $is_staging = true;
        }
      }
    }

    // Last, let's check if sync is erroring due to an IDC. If so, set the site to staging mode.
    if ( ! $is_staging && method_exists( 'Jetpack', 'validate_sync_error_idc_option' ) && \Jetpack::validate_sync_error_idc_option() ) {
      $is_staging = true;
    }

    
/**
 * Filters is_staging_site check.
 *
 * @since 3.9.0
 *
 * @param bool $is_staging If the current site is a staging site.
 */
    return apply_filters( 'jetpack_is_staging_site', $is_staging );
  }