Today we’re announcing that we intend to adopt the Chromium open source project in the development of Microsoft Edge on the desktop to create better web compatibility for our customers and less fragmentation of the web for all web developers.
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Microsoft Edge will now be delivered and updated for all supported versions of Windows and on a more frequent cadence. We also expect this work to enable us to bring Microsoft Edge to other platforms like macOS. Improving the web-platform experience for both end users and developers requires that the web platform and the browser be consistently available to as many devices as possible. To accomplish this, we will evolve the browser code more broadly, so that our distribution model offers an updated Microsoft Edge experience + platform across all supported versions of Windows, while still maintaining the benefits of the browser’s close integration with Windows. - Joe Belfiore , Microsoft Blog

In a two-in-one announcement, MS is finally abandoning Trident (forked to EdgeHTML), the once iron-fist scourge of the web. Edge was too little, too late, and still too broken. Browser engines though come and go, with names like KTHML (Konqueror) and Presto (Opera), to be replaced with WebKit, Blink (once fork of WebKit), and the obscure like Goanna (a fork of Gecko). Granddaddy, Gecko still stands tall and gets the last laugh as Netscape's ghost did the unthinkable: outlast both Internet Explorer and Edge.

It's entirely unsurprising MS is bringing Edge to MacOS as its a pretty low-lift with Chromium but doubtfully will gain any market share, as it joins the hoards of Webkit/Chromium reskins: Opera, Vivaldi, Yandex, Brave, Comodo Dragon, Amazon Silk, Samsung Internet, Torch, Slimjet, Steam's internal browser and so on.

It makes my life easier but makes Edge effectively uninteresting and forgettable.