Android 6.0 Marshmallow is now official alongside the two newest Nexus devices, and with a brand new version of the operating system there comes a new launcher. Not a completely new launcher but rather an updated version of the Google Now Launcher which people have access to currently. In Android 6.0 Marshmallow Google is reintroducing the vertical scroll for the app drawer, something which most users on stock Android are not accustomed to unless they're using a 3rd party launcher that supported it. The vertical scroll is also something that's present in other devices like HTC's One M9.
Since this is a Marshmallow-based feature those on Lollipop and prior using the Google Now Launcher won't be seeing the option to scroll vertically and things will still appear as normal. The app drawer will also feature a more prominent scroll bar along the side of the screen with letters appearing to denote the alphabetical order of the apps so users are aware of their position. If you're scrolling through the app drawer and come across Google Drive for example, the alphabetical divider on the right of the screen will display a letter "D." Aside from the app drawer, the new Google Now Launcher in Marshmallow will have integration of Now On Tap, which allows users to view detailed information cards similar to what you find inside Google Now, but from any screen on the device. Now On Tap analyzes what's on screen, and to access it users simply have to tap and hold on the screen to get detailed cards to pop up about what they're currently viewing.
There are also a couple of slight visual touch-ups, but nothing too noticeable as things still look very much full of vibrancy and color thanks to material design. In this regard there won't be much change from Lollipop. Users can also expect to see the rotating home screen again which has actually popped up in the Android M developer preview, and Google has brought it back with the consumer release of Marshmallow. This will allow users to rotate their phone while on the homescreen and have it change from portrait to landscape mode. While both the Nexus 5X and the Nexus 6P will be shipping with Android 6.0 Marshmallow out of the box, Google states that Marshmallow will be available to other compatible Nexus devices starting sometime next week when they begin pushing the OTA.