Seems even msft won't say what it's about.
https://answers.microsoft.com/en-us/ie/forum/ie11-windows_7/after-fresh-windows-7-pro-install-this-website/57292422-a854-40eb-a938-fb40da28e9de
I would not let it run.
It's easy enough to check if the firewall is enabled, to set windows update to the way you like and to install the av of your choice.
I just down/upgraded to Windows 7 from 10, Hit the IE icon by mistake, but it's asking me if I want to istall Free antivirus from Microsoft, Acrobat Reader, turn on Windows firewall, turn on Windows Update. Then it wants to run an app from onestepfreeinstaller.blob.core.windows.net.
I never ran across this before. Is this legit?

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