There are small thrusters in the nose, but the main motive force comes from the engines. They’re full hard over when they start the landing burn and that helps turn the vehicle. That and there’s LOx in the nose that’s used for ballast during decent (you can see the nose frost up some) and that LOx is dumped to feed the engines during landing which also helps the vehicle rotate. Problem is that requires a transfer tube to run down the entire length of the vehicle and there are a lot of thermal losses there with the potential that the LOx becomes gaseous before hitting the pumps which may have led to the header pressure thing Elon is mentioning (I’m taking a guess hereI haven’t seen his tweet). Edit: he mentioned fuel header, so throw my idea out the window. I was thinking the same thing! It crawled off the pad. I had to remind myself how fucking huge starship is.