protected List<SingleLogoutRequestContext> initiateSingleLogout(final String ticketGrantingTicketId,
                                                                    final HttpServletRequest request,
                                                                    final HttpServletResponse response) {
        return singleLogoutRequestExecutor.execute(ticketGrantingTicketId, request, response);
    }
Parameter to indicate logout request is confirmed.
support/cas-server-support-actions-core/src/main/java/org/apereo/cas/web/flow/logout/TerminateSessionAction.java