A few request header variables:

HTTP_REFERER=
REMOTE_ADDR=38.107.179.210
HTTP_USER_AGENT=CCBot/1.0 (+http://www.commoncrawl.org/bot.html)
HTTP_ACCEPT=text/html,application/xhtml+xml,text/xml;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
HTTP_ACCEPT_LANGUAGE=en-us,en;q=0.5
HTTP_ACCEPT_CHARSET=ISO-8859-1,utf-8;q=0.7,*;q=0.7
HTTP_ACCEPT_ENCODING=gzip