Windows 10 will still have IE 11 installed. The default browser at first launch will be the new codename Spartan or Edge browser, but the old one is still available... otherwise no corporate customers would buy the OS.
RE: IE 11 still installed under Win10.
I use an old tabbed IE-based browser because of some editing add-ons that are not longer available and have no comparable modern versions.
Last year, MS updates (which I have turned off) installed IE 10. The old browser would no longer work. I did manage to ‘uninstall’ it and return to IE9. My old tabbed browser works again.