Help guess what this button is for...

On the right, there is an unlabelled momentary switch…

another question - I want to replace that miniusb with a micro

and I want to take it off the board and mount it in the body of a (plastic) spotlight.

any idea what I should be searching for - ie, plenty of ‘surface mount’ microusb on ebay, but I’m hoping to find something that is easier to mount in a hole instead of surface mount