The Voiceflow ASR Demo is an open-source test page that showcases the capabilities of OpenAI's Whisper model using a Docker container. The demo allows users to capture audio from their microphone, transcribe it in real-time, and display the results on a webpage. By utilizing a local or server-hosted Docker container, developers can maintain control over their data and provide an efficient way to leverage the Whisper model for ASR in Voiceflow Voice Assistants.