I need to identify a name of an iPhone authentication function I saw today someone transferring data from two iPhones (not sure which models).
I suspect that was for the sake of backup/restore data one phone from another, but I'm not entirely sure about that also.  

When he needed to authenticate that the 2nd phone is really is the phone that needs that specific data, there was an animation of bunch of blue dots in shape of a circle on the 1st phone (the phone that should send the other one the data), and the 2nd one has needed to scan this animation (much like QR code) in order to get authenticated.  

What I want to know if this function is integrated in the iOS, and if it is, what is it called?  

Update: I've added a short GIF that demonstrate what I've saw.
Yes, the function is included in iOS 11 and is called "Automatic Setup".

It is designed to get you up and running quickly when you replace your phone with a new one. Essentially you power up the new, blank device - then place your old phone near the new one. A popup will ask you if you want to use Automatic Setup.

Then the animation you refer to will be shown on the new device, which you then scan with the camera on the old device.

After entering your old pass code the data from your old phone will be transferred to the new phone.