They don't need the extension if they can reach the webpage and don't mind eavesdroppers. It means I can pack much more into my bio if it's packed into my avatar instead.
A tunnel, as in a disused railway tunnel. Could build in it - rooms, short corridors, leading to other rooms, other corridors - on and on as long as money and cheap building materials allow. Fill it with disturbing symmetries: same objects in the same places over and over. Maybe a giant isopod in formaldehyde.
Tape or card over front cameras. 🙈