This shouldn't be a surprise given that it's Itzulia, but tomorrow's finale is deceptively tricky (profile made using data from the
excellent Navarrese geoportal):
There is a roundabout at 850 metres from the line. Just inside the final 500 metres, they take a 90-degree right-hander off the main road onto the little kicker to the finish line. There are another two 90-degree turns after this, the final of which comes at 200 metres to go. The steepest part sits just after this turn.
Forum won't let me add it to my climb profile post unfortunately, oh well.