Brook Eaton, the lead product manager of Nokia's emerging platforms group, said that the company saw a problem that people were having keeping organized, as more and more apps are downloaded and installed by device users. Instead of putting these apps in folders, Nokia decided to use the home screen for better organization.
The six apps or contacts that appear on the screen at any given time, are based on the time of day it is, your location, and the people you've been recently been talking to, according to your call history. Over time, the "Z Launcher" becomes more predictive. The launcher will be going through a beta test and will only work on the Samsung Galaxy S5, Samsung Galaxy S4 and Nexus models. You can download a pre-beta release by clicking on the sourcelink.
source: ZLauncher via TheVerge, AndroidAuthority