The Predictive Back Gesture in Andred 13

i think one thing that's pretty interesting in andred 13 is support for the predictive back gesture. I know very little about this, yes. Can some one explain what is? So this is a multuar effort, and i would recommend te opers to g take a look at the reper dat endroy dot com for all the details. But basically, the idea is to help cusers understand what back will do. It depends on how the applications accticture what you're going to show. Are you going back to an activity? Ar? You're removing a fragment? O you single activity in youi'm just trying to understand why we need developers to do something.