We use the handlebars library to render HTML inside the browser. Handlebars templates actually get compiled into JS functions that in turn get called via a runtime library. We install handlebars as a node module, and then we copy the runtime to the static directory and add some copyright info. The former files reside in `node_modules/handlebars`. In our installation we call `./tools/compile-handlebars-templates` to build the file `static/templates/compiled.js`. (Then in staging/prod, that file also gets minified.) For the runtime, in dev mode we serve it from the static/third directory, and in prod we minify from the static/third directory. There are also some node unit tests that use handlebars, and all the code that they use comes directly from `node_modules/handlebars`, including the runtime.