Yes, it's ES6/ES2015. It's a lambda function ("fat arrow notation"). In the parentheses you would specify the arguments. An empty pair of parentheses means that the function does not expect any parameters.

Yes, this is a shortcut for:

    const h1 = function() {
      return makeElement('h1');
    }

Arrow functions without arguments need empty paranthesis.

They also have an implicit return if you don't use {}

To add to the other explanations: it's also important to point out that arrow functions are slightly different from regular functions in that they don't redefine `arguments` and `this` so these keywords behave like any other variable would in a closure.

So it's not just a syntactic shorthand but there's also a semantic difference.

This is declaring a constant and assigning a function that takes no arguments to that constant.