candlestick, line and bar chart for value groups (open, close, high, low), volume, and adjacent close value respectively
switch between table and chart
download chart as png image
License wise: echarts.js is under Baidu's BSD 3 clause license. buttons.charts.min.js is under my BSD 3 clause license. In short, free to use in open source or commercial applications.
Your curiosity is right. The chart is tightly coupled with the excel format. So it would work as long as file format won't change and will continue to work if file format and chart input are updated together.
License wise: echarts.js is under Baidu's BSD 3 clause license. buttons.charts.min.js is under my BSD 3 clause license. In short, free to use in open source or commercial applications.