The list of start URLs that will be initially crawled is a combination of all URLs declared in the file specified here
and those which are in
Only use HTTP/HTTPS protocols in the URL.
This file might then contain something like:
http://www.funnellback.com/news/index http://www.mycompany.com/ https://some.secure.site.com/
While permission to read and edit this key is configured by read.key.start_urls_file and edit.key.start_urls_file, to fully restrict the URLs that will be crawled, you will need to also consider sec.collection-start-urls, read.key.start_url and edit.key.start_url.