How does iCloud Keychain store unsecured wifi hotspot information? Setup

I connected to an XFINITY wifi hotspot (SSID xfinitywifi) roughly 2 hours ago on my iPhone 5S (iOS 7.1.2). These hotspots require no username or password (unencrypted), but do require authenticating with a Comcast username/password at the captive portal web page after connecting. (image below)



I have iCloud Keychain enabled on my iPhone and on my MacBook Pro (OS X 10.9.4). The information for xfinitywifi was automatically copied to my MacBook Pro. (image below)



I have Safari set not to remember usernames and passwords on either device (this is unrelated to wifi and my question below, but I thought it might potentially give clarity to some readers/answerers).


Question
How (or perhaps where) does iCloud store this unsecured hotspot network information for syncing with other devices which have iCloud Keychain enabled, especially devices running OS X?
On encrypted networks, the information is stored in the Keychain Access app as an &quot;AirPort network password&quot; keychain entry. However, there is no entry for xfinitywifi in Keychain Access. I even searched for various other related strings such as comcast, etc. but found no relevant entries (see screenshot below).
As one can see you have the "Remember Networks this computer has joined" Enabled.

When you join new network, that information is saved in the 

com.apple.airport.preferences.plist


located in SystemConfiguration folder.

Obviously iCloud gets that file.

EDIT

Since you asked a new question and want to know how iCloud does that read this. (and click on User defaults database to expand)

Designing for Key-Value Data in iCloud


  To store discrete values in iCloud for app preferences, app
  configuration, or app state, use iCloud key-value storage. Key-value
  storage is similar to the local user defaults database; but values
  that you place in key-value storage are available to every instance of
  your app on all of a user’s various devices. If one instance of your
  app changes a value, the other instances see that change and can use
  it to update their configuration.




and