Her face was orange and nearly round, and didn't have a nose (not her disability; many muppets don't have noses). Her hair was a dark brown with two pigtails, one on either side.
She was added to the show in the late 1980s, when it was still dubbed Canada's Sesame Street. Her role was greatly increased on the show when it became Sesame Park, she was even more used than show veteran Dodi.
Katie is also a revision control system.