%INC    The associative array INC contains entries for  each
             filename   that   has  been  included  via  "do"  or
             "require".  The key is the filename  you  specified,
             and  the  value is the location of the file actually
             found.  The "require" command  uses  this  array  to
             determine  whether  a  given  file  has already been
             included.