Whenever a company releases a girl version of a line of products, they really just mean that those same products are now available in pink and purple. And that's basically the crux of it with Hasbro's launch of Nerf Rebelle, its new line of foam-based toys marketed to girls.
It's not that Nerf products were specifically toys for boys prior to this, but their line of weaponry and sports gear were designed with more "masculine" colors, and weren't very subtle about who they were meant to attract. But thanks to the success of feminism—but mostly how the success of heroine movies like Brave and The Hunger Games made archery "happen," and Hasbro hopes to rake in some more money by making products more appealing to girls, like its pink and black Heartbreaker bow. Even the name of the toy is gendered.