Google Search Console testing announcement bar
Google is testing a new announcement bar or tab at the top of the Google Search Console interface. The bar does not yet seem to function properly but has three levels of announcements depending on the urgency of the information.
Types of announcements. Google Search Console shows these three types of announcements bars:
Minor issue announcement
Major issue announcement
What it looks like. Here is a screen shot of what it currently looks like, although, clicking on them currently does not do anything:
Why we care. It seems Google will be able to use this to communicate issues with Google Search directly to site owners. Again, this is not fully functioning right now but I suspect it is rolling out soon.
Postscript. John Mueller from Google said "If anyone else is seeing this in Search Console, this is a test on our side of the notification functionality that shouldn't have been visible externally -- sorry for the confusion."