This is a log format defined by the W3C which can contain a variable amount of information. The format is defined at http://www.w3.org/TR/WD-logfile.html.
This log format uses a header to specify the order of the fields present in the log file.
Lire can use the following fields of the format: date, time, c-ip, c-dns, cs-uri, cs-method, sc-bytes, sc-status, cs(User-Agent), cs(Referer), cs-uri-stem and cs-username. The other fields will be ignored.