The browser includes forward and back buttons, refresh and stop buttons, favorites and settings menus, a favicon and address bar, keyboard shortcuts, full-screen mode, favorites management, and responsive design. It’s quite impressive, though the team also mentioned key missing features: support for right-click, inking, theming, and even tabs.
Microsoft explained how it packed so many features in:
The crux of the functionality stems around the powerful WebView control. Offering a comprehensive set of APIs, it overcomes several of the limitations which encumber iframes, such as framebusting sites and document loading events. Additionally, the x-ms-webview, how one declares a WebView in HTML, provides new functionality that is not possible with an iframe, such as better access to local content and the ability to take screenshots. When you use the WebView control, you get the same web platform that powers Microsoft Edge.
Unfortunately, Microsoft didn’t say how long, or how many developers, it took to build this proof-of-concept browser. That said, the team is asking anyone who might be interested in the project to report issues and contribute code.