As of the date of this post the name \"Microsoft Edge\" has just been officially announced as the default browser for the new Windows 10.
It may be premature to ask
"in case it wasn't clear, Microsoft Edge will have WebDriver support. It isn't available today, but is in development Q's? #msedgesummit" tweet from John Jansen the who is - "Microsoft Engineer. Principal Software Engineer (nee Test) Lead on Project Spartan (nee Internet Explorer)." You can find him on twitter @thejohnjansen and wait for an announcement :)