Edit: After this was posted, Ilya K pointed out that this is not a functionality provided by Apple. It's a behaviour enabled by an extension, and it baheaves as well as it can given the constraints.
So, Apple finally gave users the ability to open links in third-party apps. For example, if you use Apollo, and not the official Reddit client, you can open Reddit links in Apollo.
This functionality is implemented exactly as you would expect Apple of recent years to implement it: it loads the full page first (and triggers Reader mode if it's on), then replaces it with a call to action, then interrupts you again to see if you're absolutely sure, and only then takes to the app.