How to correctly understand such a function call?

Question

JavaScript

var a = 1;
function getFunc() {
  var a = 2;
  var func = function() { alert(a); };
  return func;
}
getFunc()();

Question about getFunc()();

Answer 1

This is the same as

var a = 1;
function getFunc() {
  var a = 2;
  var func = function() { alert(a); };
  return func();
}
getFunc();

Answer 2

This getFunc() function returns a function that remembers its environment, i.e. local variable "a".
And then comes the call to the function that was returned. getFunc() () ;

Answer 3

Calling a functor by a returned function.