A/B testing for mobile Android?

I'm really curious to understand the technology used to A/B test mobile native apps.

I searched Google and found quite a lot of products that offer A/B testing for mobile apps like Apptimize, Appiterate, Leanplum. It provides in browser drag and drop with which non-developers can make changes to the app without coding. And the changes are really fast - Once I change the color in the Desktop web browser, it automatically gets reflected in the app.

I understand that the SDK they that is running in the app is communicating the changes to/from mobile app and web. but I'm really curious to know how this is happening.. what technology is used behind to achieve this? how do I load the UI of Android xml in Desktop web browser? Any pointers?