Either more of these tests are getting out or Google is once again ramping up the number of design experiments it's running. The company is now testing a new Google homepage with an app drawer button to access many of the other services Google offers.
The button is similar to the app launcher button in the older Android interface for tablets. It's also very similar to the app launcher in Chrome, which is now available in Windows builds.
The button on the homepage opens up a panel with shortcuts to Google's most popular products or the ones it's trying to promote the most, Google+, Play, YouTube, Maps and so on.
It's not the first time Google has tried to replace the top navbar with a menu, the first time it tried, it failed spectacularly and Google eventually rolled back the change, something it very rarely does.