I have an ultra thin keyboard by logitech for my iPad air. There are keys across the top. "Home", "App switcher", "Siri", "Search" (although it doesn't put the cursor in the search field. ugh), "?????", "Keyboard, Screen Shot, rewind/play pause/fast forward, Mute, volume down, volume up, and lock. What in the world is the 5th key (?????) It doesn't do anything that I can tell. The icon looks like a globe or a circle with horizontal/vertical bent lines in it. Also, in which circumstances could you use the fn or alt/option or cmd key? And on the left and right arrows, what are the other icons on the keys? There is no documentation for this that I have been able to find. /edit: Figured it out, it's the Globe key that lets you change your keyboard.