These headers are derived from reverse engineering the UXKit framework, found within PhotoLibraryPrivate.framework on OS X 10.10.3. This is a work in progress to create useful and clean headers, like I already do for iOS private frameworks, although entire classes are being added rather than only the methods and properties being used.
Contributions are most definitely appreciated - just be sure to keep to the existing coding style.
This is free and unencumbered software released into the public domain. Refer to LICENSE.md.