At times , what happens , we get emails from fake email IDs but with the display of reputed domain name
Like say you get interview or job calls on email with the display of xyz@microsoft.com but with you click on show details you come to know who is the actual sender but if you take action without confirming the actual sender you may put your self in trouble
So to save you Gmail team took a step to save you from such email by changing the way of display of sender
See the screen shots below
You can also report regarding Phishing
For more try your self
Feel Safe When You are on Gmail