I've read a bit about it. She *probably* was identified as female at birth, raised female. But also probably has male chromosomes and maybe internal testes. It is possible she has strange sex-marking chromosomes, too.
Compared to most trans-women (who are basically biological men through-and-through), she is a case much more about intersex people than trans-people.
I could come down on either side. On one hand, most champions have genetics/physiology that gives them advantages. That is why they win. For her to be disqualified because her body is actually "built different" seems wrong, in that light.
But then again, if she has male chromosomes and even testes . . . then she is allowed to compete with other people who have male chromosomes and testes. And if she can't win there. . . well, welcome to the club of 99.9999% of people who aren't Olympic-level athletes.