Socket.disconnect() closes current connection or all?

Question

Socket.io

Perhaps a stupid question.
The phrase in the documentation baffled me.
Disconnects this client. If value of close is true, closes the underlying connection. Otherwise, it just disconnects the namespace.
Explain what this code closes

io.on('connection', (socket) => {
  setTimeout(() => socket.disconnect(true), 5000);
});

And this one:

io.on('connection', (socket) => {
  setTimeout(() => socket.disconnect(), 5000);
});

Answer 1

true => disconnects the client completely
false => disconnects from the current namespace