This parameter is used to specify an optional value for the maximum number of files the webcrawler should download during the crawl. If this limit is specified and reached then the crawler will halt cleanly at that point, even if there are more URLs in the frontier.
Alternatively, if this value has been configured for a site or domain using the site profiles mechanism then the crawler will not download any more content from the relevant site or domain.
By default the value for this is empty i.e. no limit specified.