The surf browser is very small with included tricks. So, it uses the following command to download web content:
curl -L -J -O --user-agent <useragent> --referer <referer URL> -b <cookie data> -c <cookie-jar filename> <URL>
The surf browser tells as user agent:
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.0 Safari/605.1.15 Surf/2.0
You can test it:
curl -L -J -o testfile.dat --user-agent <useragent> http://limejack.org