From the article:

> There's debate among those discussing the banner online whether the ad consists of code injected by Edge into Google's webpage, which would make it detectable and removable as part of the Document Object Model.

> It has also been suggested that the ad may come from Edge as an interface element that's stacked atop the rendered web page. We believe this is the case.

So technically not.

That's an implementation detail. What the user sees is clearly a faked up web page instead of the web page the user requested.

I consider those sign in with Google prompts, to be far worse than what Microsoft is doing.

I don't see as hijacking way because it doesn't seem to interfere with the operation of the page or modify the content. In my view, it's the equivalent of displaying a toast notification or alert with the same information. Obnoxious but I wouldn't refer to it as hijacking.