So glad you asked this. Few weeks ago when I got this Kenmore 158.9411 we couldn't remove it from the cabinet.
Eventually hubby broke off the plastic skirt cover when we were then able to see the 2 silver button screws to loosen and remove it. First part was accidental breakage then he pulled the whole brown piece off. I didn't think it was important at the time.
Still don't have machine doing zigzag.