libc6-xen 2.4-1ubuntu12.3 (i386 binary) in ubuntu edgy

 Contains the standard libraries that are used by nearly all programs on
 the system. This package includes shared versions of the standard C
 library and the standard math library, as well as many others.
 .
 This set of libraries are optimized for the Xen hypervisor, and will be
 selected instead when running under Xen.