This website uses NPM extensively. Jest, TravisCI, and Coveralls are used to provide test coverage data.
There are no custom JS assets on index.html other than Google Tag Manager. Export.html uses a browserified bundle of client-handler, excel-handler, and excel-helpers. msexcel-builder is used to export to Excel.
The production site may be several builds behind the most recent. The staging site will be the most recent build or even ahead of it!