Everything Google has said that the bot does, plus a knowledge of coding. They aren't using a LYNX style browser to render javascript and determine the position of ads on pages. They have to be using a headless type of actual browser for that - and it's a safe bet they aren't using firefox or IE or safari.
They aren't telling us how Googlebot is coded, but it's pretty easy to deduce.
They aren't telling us how Googlebot is coded, but it's pretty easy to deduce.
http://ipullrank.com/googlebot-is-chrome/ for more details