"You already have Microsoft Edge - the safer, faster browser for Windows 10," the prompt reads. It then provides the options to Open Microsoft Edge (in blue) or to Install anyway (in gray).
Microsoft has irked some Windows users in the past by pushing Edge over competitors in a variety of ways. For example, at one point Microsoft tried to force Windows Mail to open links in Edge.
@MicrosoftEdge What kind of slimy marketing cesspool crap is this Microsoft? I proceed to launch the Firefox installer and Windows 10 pops this up? If I wanted to use your browser, I would. pic.twitter.com/f7jk9sGvYA-- Sean Hoffman (@SeanKHoffman) September 11, 2018
This version of the operating system is just a test version ahead of the launch of the next revamp to Windows 10 in October. It is very unlikely that such a prompt will remain present in the finished OS that is pushed to the public, as that would undoubtedly catch the attention of antitrust regulators.
Img Src: Sean Hoffman