This file does not need to be copied.  It is here to explain the other three.

main_config.pl - main configuration file.  This file defines a subroutine
                 which will return a hash of all the templates defined by this
                 theme.  One template _can_ call another.

sitemap.pl     - the actual navigational structure of the site.  This need not
                 be tied to the directory structure even though the directory
                 structure is used to some extent in the absence of any other
                 information.  This file maps logical navigational location to
                 URL.

navmap.txt     - this maps URL to logical navigational location.  There is no
                 utility (yet) to maintain this based on sitemap.pl.
                 Hopefully in one of the next releases.