libx11-6-dbg 2:1.5.0-1ubuntu1 (i386 binary) in ubuntu raring

 This package provides a client interface to the X Window System, otherwise
 known as 'Xlib'. It provides a complete API for the basic functions of the
 window system.
 .
 This package contains the debug versions of the library found in libx11-6.
 Non-developers likely have little use for this package.
 .
 More information about X.Org can be found at:
 <URL:http://www.X.org>
 .
 This module can be found at
 git://anongit.freedesktop.org/git/xorg/lib/libX11