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

examining the entrails
 n.

    The process of grovelling through a core dump or hex image in an
    attempt to discover the bug that brought a program or system down. The
    reference is to divination from the entrails of a sacrificed animal.
    Compare runes, incantation, black art.


The Free On-line Dictionary of Computing (30 December 2018):

examining the entrails

   The process of grovelling through a core dump or hex
   image in an attempt to discover the bug that brought a program
   or system down.  The reference is to divination from the
   entrails of a sacrified animal.

   Compare runes, incantation, black art, desk check.

   [Jargon File]

   (1994-12-12)