The document discusses using a parse template component in Mule to load an external file as a template, insert data from Mule message variables into the template, and set the output as the message payload. Specifically, it provides an example of using a parse template to load an HTML template, insert employee data from a database query into the template using Mule expressions, and return the dynamic HTML as an HTTP response. The parse template allows pulling external files into flows, populating them with message data, and setting the results on the message.