Source Reference:

• Component: bbPress :: bbp-reply

  File: /bbp-includes/bbp-reply-template.php :: Trac Source Line: 1099

  			// Get email from post meta
  			$author_email = get_post_meta( $reply_id, '_bbp_anonymous_email', true );
  
  			// Sanity check for missing email address
  			if ( empty( $author_email ) ) {
  				$author_email = '';
  			}
  		}
  
  		return apply_filters( 'bbp_get_reply_author_email', $author_email, $reply_id );
  	}
  
  /**
   * Output the topic title a reply belongs to
   *
   * @since bbPress (r2553)
   *
   * @param int $reply_id Optional. Reply id
   * @uses bbp_get_reply_topic_title() To get the reply topic title
   */