Please feel free to hotlink files at code.highcharts.com. Currently the files are served from a CDN.
The CDN delivers highcharts files through a worldwide network of edge locations. When an end user requests content from code.highcharts.com, the user is routed to the edge location that provides the lowest latency, so content is delivered with the best possible performance.
For more information on how to hotlink your code, visit https://code.highcharts.com
For information on linking to the source files on GitHub, to follow the latest development, visit http://github.highcharts.com