Google has been undergoing a number of changes of late. While some of their more unique projects like Glass have been evolving, the actual company itself has seen quite a number of changes with an introduction of a new parent company in the form of Alphabet, along with some additional changes to the branding of the company in general. One of those branding changes came in the form of a newly introduced 'G' icon which now graces the main Google app. Speaking of which, it now looks like a new feature is being added to the Google app, one which should be particularly useful to those who make use of Google Now cards.
In terms of the new feature, while it is not the biggest or most useful feature that Google could of added to its Now service, it is one worth noting. In short, now when you get notification from Google Now, you will start to see a small 'G' coming attached with the notifications. This will happen in two visual ways. Firstly, it seems the actual notification will come with the small G in view in the bottom right corner. Sort of like a watermark for the notifications. The more obvious visual change, and in truth, the more useful one, is that when you do receive a notification from Google Now, you will see a much larger G icon appear in the top right corner. So before you even attempt to view the notifications, you will easily be able to identify that this is a Google Now notification.
In terms of the update, it is not quite clear how and when you can expect to see the new feature Some users are already reporting the new feature is active for them, so it likely that the feature is being turned on from Google and might not be the result of a specific update. Of course, to make use of the notifications, you do need to have the feature activated in the settings. To do so, head to Google Now (or the Google app), and then click on the menu icon in the top right corner, head down to settings and then down to 'Now Cards' and finally activate the Notifications tab.