The CloudKit framework provides interfaces for moving data between your app and your iCloud containers.You use CloudKit to take your app’s existing data and store it in the cloud so that the user can access it on multiple devices. You can also store data in a public area where all users can access it.

Core Foundation is a framework that provides fundamental software services useful to application services, application environments, and to applications themselves. Core Foundation also provides abstractions for common data types, facilitates internationalization with Unicode string storage, and offers a suite of utilities such as plug-in support, XML property lists, URL resource access, and preferences.

The Core Graphics framework is based on the Quartz advanced drawing engine. It provides low-level, lightweight 2D rendering with unmatched output fidelity. You use this framework to handle path-based drawing, transformations, color management, offscreen rendering, patterns, gradients and shadings, image data management, image creation, and image masking, as well as PDF document creation, display, and parsing.

The Core Motion framework lets your application receive motion data from device hardware and process that data. The framework supports accessing both raw and processed accelerometer data using block-based interfaces. For devices with a built-in gyroscope, you can retrieve the raw gyro data as well as processed data reflecting the attitude and rotation rates of the device. You can use both the accelerometer and gyro-based data for games or other apps that use motion as input or as a way to enhance the overall user experience.

Use the Core Telephony framework to obtain information about a user’s home cellular service provider—that is, the provider with whom the user has an account. Carriers can use this information to write applications that provide services only for their own subscribers. You can also use this framework to obtain information about current cellular calls.

Core Text is an advanced, low-level technology for laying out text and handling fonts.

Lightweight GCD based HTTP server for OS X & iOS (includes web based uploader & WebDAV server)

This collection of documents provides the API reference for the Quartz Core framework, which supports image processing and video image manipulation.