Source : Free On-Line Dictionary of Computing

PKUNZIP
     
         A program to unpack {archives} created by
        {PKZIP}, written by {PKWARE, Inc.} and released as
        {shareware}.  Versions exist for {MS-DOS}, {Microsoft Windows}
        and {Open VMS}.  PKUNZIP is no longer distributed, its
        functions having been incorporated into PKZIP.
     
        (1999-01-07)