How does this work, does some mechanism replace the actual tape drive in the Datasette? Can you just use the tape port with the gadget or does it somehow need the tape drive? How do you access the HTML applications, how is the translation to PETSCII handled?

I have no idea how this could work but as a long time Commodore 64 fan I'm interested. The link won't load for me, sadly. Can somebody give me a quick rundown on how I can host HTML apps inside my Commodore Datasette tape drive?