Or are we just getting the site design update we were promised where we told the SE folks, sure, we'd love a site update but it's not enough: we want full graduation.
Even if it's just the update, that's a good thing.
Where do we stand?
It appears to be a glitch. It's an April Fools Joke
Worldbuilding (which graduated a long time ago) has the same half-finished 1999 design.
To make it go away, click the clock icon on the top right of every page that has it. You usually have to click it twice. Then you get a page with ordinary formatting.
Looking on META. It appears to be an early April Fools joke. What testing is done on 'April Fool' pranks?
I first checked https://area51.stackexchange.com/proposals/1623/writers and it showed only 8 Qs/day, so I worried that we were being demoted down to 1990/myspace layout!