When Kale goes Super Saiyan, she enters into a berzerk state with green hair that has been referred to as 'Legendary Super Saiyan,' which suggests that the original myth Vegeta referred to may have been about this form rather than the standard Super Saiyan form. Ahead of Broly being brought into the canon by the film Dragon Ball Super: Broly, Kale canonized the form associated with Broly in his early, expanded universe appearances in the original DBZ-era films. Kale is another Universe 6 Saiyan who has a special role in the history of the Dragon Ball canon.
The second of the two blue Leaders, which you can see above, features Kale. We previously showed off the first blue Leader card of the set, which features Cabba.