ruby-multibitnums-dbg binary package in Ubuntu Precise i386

 Multibitnums is Ruby class library, handling multiple multi-bit data
 packed in a C string. The number of bits is fixed to an arbitrary
 value. For example, it can accommodate 11-bit integers.
 .
 This package is provided primarily to provide a backtrace with names
 in a debugger, this makes it somewhat easier to interpret core
 dumps. Most people will not need this package.

Source package