The symbol is your current position as interpreted by your browser from where your internet provider gives for your IP address
Well spotted Niall... I'd forgotten about the web location 'You are here' Icon
I turned mine off years ago...
I turned mine off years ago when the MyDrive Web Route planner decided that I lived in a different town 30 + Miles away, according to Google Street view its a tiny brick building at the end of a Cul-de-sac