Thanks for starting this topic. Not only did I see the icon and wonder what it was, when I clicked on the icon I selected the "Get Win 10" (I assume) option assuming it would take me to an informational page. It did do that but it also set my computer to receive the update when it becomes available the end of July, at their convenience and using up 3GB of my cellular data. There is no option to get rid of it once it's there. Un-installing the above mention update got rid of the update option as well as the taskbar icon.
Again, thanks much!
******Please just read this part and don't steal this thread by responding, but the main reason I see for not installing W10 is that you cannot opt out of future updates or when they are installed which would eat up my cellular data when I prefer to wait until WiFi is available.******