The penultimate stage is a 31 km individual time trial. 31-km stage is actually not as hilly as the published profile suggests.
“The only individual time-trial of the 105th edition measures 31 kilometres. But the geography of the Basque Country doesn’t make it one for pure time-trialists and should suit the puncher type riders. If the hierarchy for the podium is not established, the climbers who are still fresh at the end of the Tour will have their card to play.” –Christian Prudhomme