ocaml-compiler-libs 3.11.1-4 (amd64 binary) in ubuntu lucid

 Objective (OCaml) is an implementation of the ML language, based on
 the Caml Light dialect extended with a complete class-based object system
 and a powerful module system in the style of Standard ML.
 .
 This package contains several modules used internally by the OCaml
 compilers. They are not needed for normal OCaml development, but may
 be helpful in the development of certain applications.