It seems Google is testing a new design layout for the Google Play Store app on mobile which adds a notification section to the proceedings. At the moment this seems to be a limited access testing phase and so it is more likely that most Android device owners will not see the new feature on their device. To check whether the new feature is live, open the Google Play Store app, click on the menu icon in the top left-hand corner, and those part of the testing will see a new "Notifications" tab positioned just below the "My apps & games" tab at the top.
In spite of this new tab having now been spotted as available to some users, it is still not entirely sure what the feature will offer. As those have spotted the feature are not getting much feedback when trying to use it at present. When clicking the notifications tab, the Play Store app opens a new notifications page which is currently accompanied by a "you're all caught up" message. Of course, with this being a notification-based tab, it is expected that some form of short messages will be available and likely advising of new information regarding any and all apps the user has installed on the device.
How this will differ from the information that is currently presented to most Android device owners through the 'My apps & games' tab remains to be seen. As that is also a one-click link to another page which provides information on installed apps, including when new updates are available and so on. It is worth keeping in mind that while the new notifications page links through to a settings page for notifications – which explains the user can get notifications on when app updates are available, when Google Play Store automatically updates apps, when pre-registrations become live, and when deals and promotions launch – these are all aspects which are already accessible to Android device owners, irrespective of whether they are seeing the new dedicated notifications tab or not. So all that is new at the moment is the actual notifications tab and the link through to a notifications page which at present does not provide any further insight.