>>956552Sure, but that bike essentially has an adjustable seat tube angle. Yes that does change the top tube length but that's just a consequence. It's like saying that by changing tyre size you're changing the bottom bracket height, whilst technically true it's not the primary objective nor the best way to achieve it.
>>956553It only needs one so it's probably on the left side hidden from view, either a downtube shifter or bar end. Either that or it's just not cabled up, the image is too small to tell for certain where the cable would come from the derailer (it looks like it may exit from the rear and loop round).