_title = function (config, dt) {
	var title = _stringOrFunction(config.title, config, dt);

	return title === null
		? null
		: title.indexOf('*') !== -1
		? title.replace('*', $('head > title').text() || 'Exported data')
		: title;
}
Get the title for an exported file.

@param {object} config	Button configuration