Its an 'Apple' ESC key ..... Stupid !!!
"Apple have invented the Escape key on a keyboard. Expect the patent application imminently."
You have missed the genius of it !!!
This is an 'Apple' ESC key !!!
The clever part is that it looks just like a 'normal' ESC key, operates just like a 'normal' ESC key *but* includes all the extra Apple goodness for 'Free*'.
* 'Free' meaning $1000 in AppleSpeak as per usual. :)