@jcrabapple Meh. Microsoft, like all other big companies, will respond to legal process. Given that Microsoft's recent operating systems basically require you to log in to their cloud at startup, this is not particularly surprising to me.
And if motivated to pursue a threat actor who is actively harming their customers, Microsoft can tell a great deal about users. As can Google, or FB/Meta. I always said that if just two of those companies decided to find someone responsible for something, they probably could if they shared information.