Server response of the future?

response.http

HTTP/1.1 200 OK
Content-Type: application/foo+json;    # Web applications typically do and should use JSON as the semantic data source
                                 # If your mobile device has an app for "application/foo+json", auto-launch app to handle resource
Link: <http://foo.com/ui.html>; rel="renderer"    # HTML page to use to renderer it
Link: <http://foo.com/ui.ipa>; rel="ios.renderer"    # Recommended device-specific app for this resource
Link: <http://foo.com/schema>; rel="describedby"   # schema describing the JSON structure so that search engines can crawl it
...