code: @Nullable
    public static String getGuestUserDisplayName (@Nonnull final Locale aDisplayLocale)
    {
      ValueEnforcer.notNull (aDisplayLocale, "DisplayLocale");
  
      return ESecurityUIText.GUEST.getDisplayText (aDisplayLocale);
    }
docs: Get the display name of the guest user in the specified locale.
  
  @param aDisplayLocale
  The locale to be used. May not be <code>null</code>.
  @return <code>null</code> if no translation is present.