I've been using Next.js for a couple of years now so I haven't been to React's website in quite some time. I was surprised that on the landing page when you come to the "Full-Stack" section and routing, they mention using Next.js or Remix. When did this happen?

This came out as part of the new React docs site at React.dev, which was launched earlier this year. (There's been a lot of debate about that within the React community since it happened.)