libsm6-dbg 6.8.2-10.3 (amd64 binary) in ubuntu hoary

 This package is useful to provide a backtrace with symbol names in a
 debugger; this facilitates interpretation of core dumps, and aids in finding
 logic errors in programs using this library (or the library itself). The
 library is installed in /usr/X11R6/lib/debug and can be used by placing that
 directory in the LD_LIBRARY_PATH environment variable when the code to
 be debugged is executed.
 .
 Non-programmers will likely have little use for this package. See the
 libsm6 package for further information.