You are correct that this functionality was removed from Next.js in v15.0.0
(See: breaking: remove geo and ip from NextRequest: #68379)

Due to how geo was removed from Next.js, even though we are passing the values along, the framework doesn't pass these on to the middleware handlers as before. We are currently supporting multiple versions of Next.js, so the supporting code you linked continues to ensure we can support this feature in v13 and v14, though I completely understand the confusion this may have caused.

There is still a way to access the same geo values as before on a site that's deployed to Netlify, and that's via the Netlify-specific Context object.

Example:

export async function middleware(request: NextRequest) {
    // @ts-expect-error Netlify global
    return Response.json({ geo: Netlify.context.geo });
}

Hope that helps clear things up!

@mrstork, thanks for confirming the behaviour. I had completely forgotten that the global Netlify context was available within middleware. It would be good to have the documentation for both OpenNext and Netlify updated to call this out and avoid any confusion others may also have.

In any case, I have used the below code which works really well, especially for local testing outside of the Netlify CLI by hooking into the x-nf-country header.

type Geo = Exclude<(typeof Netlify)['context'], null>['geo']

let geo: Geo | undefined
try {
  geo = Netlify.context?.geo
} catch {}

const country =
  geo?.country?.code ??
  request.headers.get('x-nf-country')