Wii mote and classic pad clips?

[WazMeister]

Whats the button on top of the classic control for, to move the slots on the back?

Notice some holes at bottom of wii mote too

What do all these clip on, The Classic pad has 2 slots and u can havea button to open em?

[Ouenben]

I noticed this too, nothing in the manuals so maybe it's just there for future if Nintendo decide to make a clip that links the 2 controllers.