A few days ago, Microsoft confirmed the rumors that their Edge browser, the default web browser of Windows 10, will move to a Chromium-compatible web engine in the Desktop version. Now, a new option of the Edge Insider Program allows joining it to get early access to the upcoming version of the browser.
As you may already know, Chromium is an open-source version of Google Chrome, that doesn't include certain proprietary components. Its rendering engine, Blink, along with other technologies, is widely used as a base for many other modern browsers, including Vivaldi and Opera.
At this moment, Microsoft is not going to discontinue EdgeHTML and Chakra, the company's in-house engines for JS and content rendering, since both are heavily used in UWP/Store apps. But in the future, Microsoft will switch to the Chromium engine for web views too.
So, if you are interested in trying the new app, you can be a part of its development if you want, by signing up to be an Edge Insider. You can sign up here.