Update 1/13: In another update (version 126.96.36.199), the normalized app icons were removed and are now back to their original size. The feature was likely just a bug. This update also fixes the gap between the favorites tray and onscreen buttons in landscape and the non-grayed out buttons when the launcher is opened.
The Google Now Launcher received quite a few updates in version 188.8.131.52 of the Google app. The launcher, which resides within the Google app, now has landscape orientation and normalizes the size of app icons.
Landscape orientation for the homescreen was first seen in the Android M previews, but was removed for the final release of Marshmallow. There is now an ‘Allow rotation’ option in the Google app settings under homescreen. Enabling it will allow your homescreen, app drawer, and Now card stream to rotate vertically. Of course, system-wide Auto-rotate has to be enabled as well.
The app drawer in landscape gets an extra column of apps. In this update, app icons in the drawer and homescreen are now similar in size to one another. This change can especially be seen with apps that have larger icons, like Snapchat’s:
As the update was first released to those who are on the Google app’s beta channel, there are some bugs. On the Nexus 5X, the landscape view of the homescreen has a huge gap between the app favorites tray and the onscreen buttons. (Look at header image.) Additionally, when the app drawer is in landscape, the onscreen buttons are not get grayed out like the rest of the background.
There is also a new animation when activating and exiting out of Now on Tap. The update is currently available to users who are on the beta channel of the Google app. Regular users should expect a similar, bug-free update in the coming days.