By default, Microsoft gets to see your location, keystrokes and browser history – and listen to your microphone, and some of that stuff is shared with “trusted [by Microsoft, not by you] partners.”
You can turn this all off, of course, by digging through screen after screen of “privacy” dashboards, navigating the welter of tickboxes that serve the same purposes as all those clean, ration-seeming lines on the craps table: to complexify the proposition so you can’t figure out if the odds are in your favor.
Oh, and if you’ve already chosen to use Firefox as your default browser, Microsoft overrides your decision when you “upgrade” and switches you to the latest incarnation of the immortal undead monster formerly known as Internet Explorer.
For fucks sake, Microsoft. You’re not supposed to be a fucking spyware vendor.