How Do Macbooks Automatically Connect to Xfinity Wifi I have a MacBook that has automatically connected to Xfinity hotspots ever since I logged into a friends apartment wifi years ago. They now live outside the US, so I doubt they still have an account. 

How is the information that allows me to automatically connect stored? I was looking in the keychain access app and could not find any stored passwords / keys. For my other computers Xfinity will throw a popup asking me for account information.

I was hoping I could figure out how to copy the password / validation key information to other computers I own for wifi access on the go. Perhaps it is handled differently, but either way it seemed an interesting question to learn the answer to. Thanks!
That information is in your keychain.

Just enter the name of the WiFi in the search box in key chain.

If you do not know the name look it up.

All the networks that your computer has ever joined are saved in System Preference > Networks > advanced.

UPDATE.....Xfinity WiFi is not actually called Xfintiy, it is called Comcast.

Use Comcast when searching in your keychain.

I just looked up mine and there it is, even so I do no longer use it.