https://twitter.com/hamzasood/status/874365037913178117
The new control centre in iOS 11 is extendable by addition of modules. This project contains a few example modules.
A module is a loadable bundle with a principal class that conforms to CCUIContentModule. Modules have to placed in /System/Library/ControlCenter/Bundles in order to be discovered. However a module will be ignored unless it has been whitelisted by adding its bundle identifier to /System/Library/PrivateFrameworks/ControlCenterServices.framework/ModuleWhitelist.plist.
Modules should favour UI elements in ControlCenterUIKit as opposed to UIKit so that they'll better match the control centre theme.
Note that modules all get loaded into the same process. So class names should be such that the chance of a collision is minimal.