protected function send_debug_email() {
    $update_count = 0;
    foreach ( $this->update_results as $type => $updates ) {
      $update_count += count( $updates );
    }

    $body     = array();
    $failures = 0;

    /* translators: %s: Network home URL. */
    $body[] = sprintf( __( 'WordPress site: %s' ), network_home_url( '/' ) );

    // Core
    if ( isset( $this->update_results['core'] ) ) {
      $result = $this->update_results['core'][0];
      if ( $result->result && ! is_wp_error( $result->result ) ) {
        /* translators: %s: WordPress version. */
        $body[] = sprintf( __( 'SUCCESS: WordPress was successfully updated to %s' ), $result->name );
      } else {
        /* translators: %s: WordPress version. */
        $body[] = sprintf( __( 'FAILED: WordPress failed to update to %s' ), $result->name );
        $failures++;
      }
      $body[] = '';
    }

    // Plugins, Themes, Translations
    foreach ( array( 'plugin', 'theme', 'translation' ) as $type ) {
      if ( ! isset( $this->update_results[ $type ] ) ) {
        continue;
      }
      $success_items = wp_list_filter( $this->update_results[ $type ], array( 'result' => true ) );
      if ( $success_items ) {
        $messages = array(
          'plugin'      => __( 'The following plugins were successfully updated:' ),
          'theme'       => __( 'The following themes were successfully updated:' ),
          'translation' => __( 'The following translations were successfully updated:' ),
        );

        $body[] = $messages[ $type ];
        foreach ( wp_list_pluck( $success_items, 'name' ) as $name ) {
          /* translators: %s: Name of plugin / theme / translation. */
          $body[] = ' * ' . sprintf( __( 'SUCCESS: %s' ), $name );
        }
      }
      if ( $success_items != $this->update_results[ $type ] ) {
        // Failed updates
        $messages = array(
          'plugin'      => __( 'The following plugins failed to update:' ),
          'theme'       => __( 'The following themes failed to update:' ),
          'translation' => __( 'The following translations failed to update:' ),
        );

        $body[] = $messages[ $type ];
        foreach ( $this->update_results[ $type ] as $item ) {
          if ( ! $item->result || is_wp_error( $item->result ) ) {
            /* translators: %s: Name of plugin / theme / translation. */
            $body[] = ' * ' . sprintf( __( 'FAILED: %s' ), $item->name );
            $failures++;
          }
        }
      }
      $body[] = '';
    }

    $site_title = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );
    if ( $failures ) {
      $body[] = trim(
        __(
          "BETA TESTING?
=============

This debugging email is sent when you are using a development version of WordPress.

If you think these failures might be due to a bug in WordPress, could you report it?
 * Open a thread in the support forums: https://wordpress.org/support/forum/alphabeta
 * Or, if you're comfortable writing a bug report: https://core.trac.wordpress.org/

Thanks! -- The WordPress Team"
        )
      );
      $body[] = '';

      /* translators: Background update failed notification email subject. %s: Site title. */
      $subject = sprintf( __( '[%s] Background Update Failed' ), $site_title );
    } else {
      /* translators: Background update finished notification email subject. %s: Site title. */
      $subject = sprintf( __( '[%s] Background Update Finished' ), $site_title );
    }

    $body[] = trim(
      __(
        'UPDATE LOG
=========='
      )
    );
    $body[] = '';

    foreach ( array( 'core', 'plugin', 'theme', 'translation' ) as $type ) {
      if ( ! isset( $this->update_results[ $type ] ) ) {