what component is labelled as A and K

[Drake_dragon54]

Hi I got some pedalpcbs some of them have a 2 hole component labelled A K with a box around the hole for K what goes here?

 

[Nostradoomus]

Your LED. A is the Anode or positive leg (longer). K is cathode or negative, shorter leg.

 

[Drake_dragon54]

Your LED. A is the Anode or positive leg (longer). K is cathode or negative, shorter leg.

Thanks!