Internet Explorer was, for many years, the default browser used by Windows operating systems. It was a browser with its strengths, but with some weaknesses that were even reason for a "meme." More recently, the Redmond company, probably due to the exodus of users switching to Firefox and especially Chrome / Chromium, decided to launch Microsoft Edge, a new browser that left a very good taste in the mouth, but could be improved.
The original version of Microsoft Edge used the company's own engine called EdgeHTML, but in 2018 they decided that one of the best ways to further improve their browser was to start using the Chromium engine, used by the vast majority of popular browsers and is open source. The one referred to in some media as "Edgium" (Edge + Chromium) has been available in trial versions for months, but as of today it will be updated automatically in Windows 10. It will also do it in Windows 7 and Windows 8.x.
Microsoft Edge becomes compatible with Chrome extensions
It is important to mention that Edge will be fully compatible with Internet Explorer, which means that it is backward compatible (there is still a lot of content that is only compatible with the old browser). On the other hand, it also includes a tool called Collection that allows us to save content such as images or text and has simplified privacy functions, it is compatible with PWA (Progressive Web Apps), several user profiles can be used, it has a reading mode, dark mode and PDF viewer.
The update will be automatic and unavoidable for all users except Windows Business, who can use the tool available at this link to block update. Taking into account the improvements and that there will be backward compatibility, right now I can't think of any reason to use the tool, but it is there for those who need it.
With regards to Linux version, Microsoft has not used the moment to give more details, so we have to stay with the promise that it will come sometime.