I was very confused as well. It turns out that the College Board has started offering an AP Research course. It’s essentially a year-long course in which they write a research paper of 4000-5000 words.
Unless this course is done under the supervision of a college/university professor, I’m skeptical of its value for a student. I mean, the credit is nice, and I suppose the practice is nice, but I don’t think most would see it as equivalent to an independent study at the college level (which is the kind of thing you’d get credit for in college). I think the value is that it gives you early practice and may make you more appealing to be a research assistant in a lab, but the university-level RA experience is what’s going to be valuable to graduate schools.
I mean, if you have no other place to apply the credit, sure, why not? Use it towards the GE requirements. But if she has other APs that will get her out of other GE requirements, then I’d recommend using those.