Source : Free On-Line Dictionary of Computing

runes
     
        1. Anything that requires {heavy wizardry} or {black art} to
        {parse}: core dumps, {JCL} commands, {APL} or code in a
        language you haven't a clue how to read.  Not quite as bad as
        {line noise}, but close.
     
        Compare {casting the runes}, {Great Runes}.
     
        2. Special display characters (for example, the high-half
        graphics on an {IBM PC}).
     
        [{Jargon File}]