If you click on export icon, you will given options to choose like on which format you need to export the data. Just click on anything you wish. You can see that the data is being send to the server http://export.highcharts.com/ in the top left side.
exporting: {
chartOptions: {
plotOptions: {
series: {
dataLabels: {
enabled: true
}
}
}
},
scale: 3
}