Default Parameters for Your Functions

Can anyone tell me what the empty parenthesis does and its usage. I wonder why this empty parenthesis is placed at the end of the curly bracket.

const increment = (function() {
  "use strict";
  return function increment(number, value = 1) {
    return number + value;
})( ); // <- this empty parenthesis, why is that placed and what is it used for
console.log(increment(5, 2)); // returns 7
console.log(increment(5)); // returns 6

See the following existing threads:

I know this ( ) is a function. I am asking what this ( ); being placed at the end of the curly bracket does.

It has now been solved.