A red sex link can be made several ways, using several different strains. Most of the hatcheries assign their own "brand" name to the crosses, for marketing purposes. If they just sold them as "mutts" or mixes, who would feel good about that? There is a purpose behind these mixes. Sex linking is important to the laying industry, as there's no need for the cockerels whatsoever.
The whole reason we have these brand names is so that when asked, "What kind of chicken is she?" We can answer, "Oh, she's a Red Star, a Cinnamon Queen, a Comet, a XXXXX XXXX. It gives the owner a sense of identity.
Your pullet is a pretty bird. May she live happily and healthily. Enjoy her.