/*jslint browser */
/*global require */
(function () {

    "use strict";

    let jQuery = require("jquery");
    jQuery(function onDOMContentLoaded() {

        // Polyfill picture element
        require("picturefill");

        // And remember your semi-colons

    });
}());

@@ -76,14 +76,16 @@
     
-let jQ
+const jq
 uery
@@ -115,9 +115,9 @@
    j
-Q
+q
 uery

Use const for library