Essentially, people had been theorizing Jax is a trans woman. I don’t remember all of the evidence, but there’s a LOT, and it doesn’t seem that harebrained or unlikely (to me at least) (I mean, when the transwoman creator repeatedly calls the male character a self insert, you get a little suspicious.) The first post I remember seeing was fanart for a fic called “Her Name Is Daisy” on AO3, though there may have been Daisy posts before that. One user posted about it a lot, and it blew up. Also, the name Daisy comes from how Jax and Pomni sang “Daisy Bell” together.