Google has decided to start showing more information to Gmail users about who email is actually coming from. It's that you're getting new information exactly, but more that it's just more readily visible.
When you get a message from someone who isn't in your Gmail contacts, Google will now show the sender's email address in the header. Even when a site sends you something on behalf of someone, it will show you who actually send it. Like if your friend sends you something via a share link on an article, it will make it more clear that this is coming from your actual friend (as opposed to the site).
Google software engineer Ela Iwaszkiewicz writes on the Gmail Blog:
I recently received an email from what looked like my bank saying I should update my account, but it looked a little weird. I clicked on the “show details” link and quickly learned it wasn’t from my bank after all; instead of being sent from First National Bank’s real email address, this message originated from a random South African domain. If I hadn’t viewed these details, I could have been tricked — it wasn’t entirely obvious that this email was a fake.
Phishing messages are a form of spam that attempt to deceive recipients in order to gain access to their personal information. Starting today, Gmail will automatically display more information about the origin of certain messages you receive so you can be better informed and protect yourself from getting tricked. If someone fakes a message from a sender that you trust, like your bank, you can more easily see that the message is not really from where it says it’s from.
Additionally, Gmail will now display a warning when it detects suspicious emails. You can always report messages you think are phishing attempts.
More information about the changes is available in the Gmail Help Center.