https://techcrunch.com/2017/11/28/microsoft-shows-off-windows-sets-a-tabbed-app-interface-that-puts-a-web-browser-everywhere/

Just a few weeks after the major launch of Windows 10 Fall Creators Update, Microsoft is already looking towards what’s next as the company looks to test features that could fundamentally shape how you use web browsers.

Today, Microsoft announced a new feature tentatively called “Sets,” a fairly significant retooling of how web browsers and apps operate philosophically in Windows. Rather than having Edge users manage a set of browser windows filled with relevant tabs to a particular task, Microsoft wants to build those tabs directly into apps. If you’re writing up a Word document and needing to research topics online to integrate into it, rather than venturing to a new browser window, you’ll be able to open Edge inside the app with a new tab and get to surfing. You’ll also be able to pull up file windows.