The Free On-line Dictionary of Computing (19 January 2023):

flarp

   /flarp/ [Rutgers University] Yet another metasyntactic
   variable (see foo).  Among those who use it, it is
   associated with a legend that any program not containing the
   word "flarp" somewhere will not work.  The legend is
   discreetly silent on the reliability of programs which *do*
   contain the magic word.

   [Jargon File]


The Jargon File (version 4.4.7, 29 Dec 2003):

flarp
 /flarp/, n.

    [Rutgers University] Yet another metasyntactic variable (see foo).
    Among those who use it, it is associated with a legend that any program not
    containing the word flarp somewhere will not work. The legend is discreetly
    silent on the reliability of programs which do contain the magic word.