It's an example app with server who connect across pi blockchain.
This is a client who communicate with the donatepi-server, and with him, done the requests to the pi blockchain.
The core files can be considered public/index.html
and public/scrips.js
.
The other files are an implementation of a node server with basic pattern for serve static files, precisely those contained in the public/
folder.
Here you can see a running example.