My first impression when seeing that there is "Why would I look at the documentation for Stackoverflow, I know my way around this website for what I need to do".

Only in the desktop layout, no tablets or phones.

Anyway, who looks at the navbar? People get there by googling a problem they are having now. They're in hurry, no time to look around.

I think he's talking about the big unnecessary "Welcome Back!" box that appears randomly.

Exactly. Doc-beta link mentioned above is at the area I never focused on. Jobs, >Documentation<, Tags.