My middleware matcher for next-intl looks like this:

  matcher: [
    "/",
    "/(about|changelog|pagexyz)/:path*",
  ],

when I visit /foo (which doesn't exist) I see the nextjs 404 page and receive an error in the console (NEXT_NOT_FOUND). when I add

"/((?!api|_next|_vercel|.*\\..*).*)"

to the matcher everything works. Why?

I currently receive tons of NEXT_NOT_FOUND errors on Vercel due to things like favicon.ico, etc. - but why?