See http://www.softwareishard.com/har/viewer/?inputUrl=http://journeymonitor.com/api/testresults/301CA817-1972-4E74-9C71-10567FC424A1/har.jsonp for an example. Also see http://stackoverflow.com/questions/39923498/selenium-stuck-with-firefox and http://stackoverflow.com/questions/40789893/webdriver-for-firefox-browser-starts-w-empty-page-hangs-for-2-min-restarts.