I didn’t mention her in this post primarily because my understanding is that she didn’t work on the Difference Engine (which is in the video), but rather on Babbage’s “Analytical Engine” — which may or may not have ever been fully designed. At least, I can’t find any sources stating that the Analytical Engine reached a detailed design stage, unlike the Difference Engine.

From what I can tell, the Difference Engine isn’t really programmable — although you can change the values of its inputs. The Analytical Engine was supposed to be a fully programmable mechanical computer (i.e., with changeable algorithm and inputs), a much tougher nut to crack mechanically.