These are Katrina's basic standing attacks off a jab. She'll be 4 button like the others so for combos medium punches/kicks are accessed by pressing the lights twice in a combo.
The Jab is lazily animated since its just a poke, also from a design stand point she can't jab with her screen-right arm due to her breast being so big they would obscure that. Or at least some of the animation for it.