DuckCorp Dico

Found one definition

1.                 From The Free On-line Dictionary of Computing (19 January 2023):
                   
   
   
                   
                     
   DUEL
      <programming> A front end to gdb by Michael Golan
      <mg@cs.princeton.edu>.  DUEL implements a language designed
      for debugging C programs.  It features efficient ways to
      select and display data items.  It is normally linked into the
      gdb executable, but could stand alone.  It interprets a subset
      of C in addition to its own language.
      Version 1.10.
      (ftp://ftp.cs.princeton.edu/duel/).
      (1993-03-20)