You can find this list of pending updates—which does not appear yet for install in Windows Store—by opening the Event Viewer and searching the System log for “Installation Ready”.
What I found when I did this was the following:
Installation Ready: The following updates are downloaded and ready for installation. To install the updates, an administrator should log on to this computer and Windows will prompt with further instructions:
• microsoft.windowsphotos (Photos)
• Microsoft.ZuneMusic (Xbox Music)
• microsoft.windowscommunicationsapps (Mail, Calendar, People, Messaging)