If this plug-in is enabled, and there is a file on the same theme level as the static page URL level, then that theme file will automatically be loaded as the template file.
Example
For the static page URL: “http://example.com/foo/bar/”
Theme directory: “/wp-content/themes/mytheme/foo/bar/index.php”
will be loaded as the template file if it exists.
*If enabled themes have a parent-child relationship, then the file for the child theme will be loaded with precedence.