[OT] What do you do with your F-8 key?

[Richmond]

  Still fudging around to find a key that is not used for much else on a 
keyboard;

would be grateful iff (i.e. "if and only if") you use your f-8 key for 
any specific
purpose you could respond (and, no, I'm not interested in "for cleaning the
wax out of the dog's ears"), indicating your OS of choice, and whether that
is an OS setting or a personal tweak.

sincerely, Richmond.