Why is there a 🔧 icon showing at the top of my mobile phone screen?

[AC Question]

Does this mean something on my phone that I'm not aware of needs to be fixed? If not, how do I make this annoying wrench icon go away?

 

[Rukbat]

Pull the notification bar down and you'll probably see a notification from Google. There have been changes, so everyone is getting a notice about what they are.