If you're one of the millions of people who've already upgraded to Windows 10, you've probably noticed that the OS changed your default apps. Your main browser, for instance, suddenly became Microsoft Edge after the upgrade -- something Mozilla finds "disturbing," especially since the platform actually made it trickier to switch back to Chrome, Firefox or any other browser. In anopen letter to Microsoft head honcho Satya Nadella, Mozilla's CEO Chris Beard revealed that the non-profit got in touch with the Windows 10 team when it got wind of the change, but that "didn't result in any meaningful progress."

http://www.engadget.com/2015/07/31/mozilla-windows-10/