For release notes and other info pointers:
http://sites.google.com/site/fullycapable/
See GIT repository for detailed source history
https://git.kernel.org/cgit/linux/kernel/git/morgan/libcap.git/
Or simply download the source:
git clone git://git.kernel.org/pub/scm/linux/kernel/git/morgan/libcap.git
The license for this library is here:
https://git.kernel.org/cgit/linux/kernel/git/morgan/libcap.git/tree/License
please submit patches compatible with this to morgan at kernel.org.