Where can I find the Link-OS SDK for iOS?

I'm evaluating the QLn printers for integration with an in-house iOS app. I'm trying to get my hands on the iOS SDK for communicating with the printer, I've visited this page and downloaded the OS X installer, but it fails silently when I attempt to run it on the latest version of MacOS (Sierra). I'm also not sure why this is an installer/DMG at all since I am just looking for the files to include in my app, and perhaps some instructions/sample code etc. What is it attempting to install?

 

Any ideas where I can get hold of the SDK?