All I'll say is I have no opinion about this particular person, but she definitely fits the profile, i.e. a law clerk for a SCOTUS Justice. For some reason, I am not discounting a rogue clerk for a majority Justice having leaked it. My only reason for not discounting it is a majority Justice clerk would be more likely to have access to a draft opinion.
There's often a fair amount of horse trading internally in cases like this, though, trying to peel one more Justice off to make it look more legitimate and less like a reckless 5-4 curbstomp spitting on stare decisis. So sometimes they'll take something like a draft dissent and look at it and address some actual legit criticism, and mold the opinion to represent the majority opinion more clearly or make it even palatable to some of the previous dissenters.
If you can get actual unanimity on an issue by narrowing the scope of the basis for the decision, you'll do this.
Roberts hates this kind of drama shit and if the ultimate opinion isn't as bad as it looks to be, it will probably be from him massaging it a bit and working out deals.
We really don't know at what point in the deliberations they were at which is yet another reason it was absolutely reckless and irresponsible to leak this now. I also strongly suspect it constitutes a "crime of moral turpitude" under bar rules, one serious enough to justify disbarment or refusal to admit.