From the js source - This application uses other third-party javascript components distributed under appropriate licenses. For more information, see the follow

From the js source - This application uses other third-party javascript components distributed under appropriate licenses. For more information, see the following files at http://trello.com/js/lib/ http://trello.com/js/lib/ backbone.js, highcharts.js, json2.js, markdown.js, socket.io.js, underscore.js, ...apart from jquery/jquery-ui.