The application is a web server that handles calculator UI generation and logic through dynamic HTML and Javascript. It is written entirely in C and uses no third-party libraries. Firefox is launched to access the web server running on localhost. When the user presses a calculator button, an AJAX call (XMLHttpRequest) is sent to the application, indicating the button press. When "=" is pressed, the calculation is processed by accessing Google. The response is "screen scraped" to extract the result and sent it back to the client.