libcap is a library for getting and setting POSIX.1e (formerly POSIX 6) draft 15 capabilities.

More information (POSIX 1e and 2c drafts):  
http://wt.xpilot.org/publications/posix.1e/download.html

Usage tutorial (Olaf Kirch: Using Capabilities - 2002): 
http://www.lst.de/~okir/blackhats/node125.html 

Linux Capabilities FAQ 0.2 (by Boris Tobotras - 1999):
  ftp://ftp.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.2/capfaq-0.2.txt

If you uninstall this package, you will need to manually remove the
/usr/include/sys/capability.h header.