I thought that was just based on URLs. Similarly when I open a yelp.com link in my mobile browser it asks me whether to open it using the Yelp app or the browser.
This, on the other hand, is Google sending you directly to a yelp://-or-somesuch URL.
Basically, Google is taking charge of doing the client-negotiation step, so (if this catches on) sites don't have to worry about doing that redirect themselves any more.
For example, if you have Twitter for iOS installed on iOS 9 and you click on a link to https://twitter.com in a Google search result, you switch into the app's main screen immediately.
[0]: https://developer.apple.com/library/prerelease/ios/documenta...
I fail to see the difference between this and deep linking within the app.