diff --git a/build/media_source/com_templates/joomla.asset.json b/build/media_source/com_templates/joomla.asset.json
index 3bba1c93d46f2..3e663870697d0 100644
--- a/build/media_source/com_templates/joomla.asset.json
+++ b/build/media_source/com_templates/joomla.asset.json
@@ -5,6 +5,30 @@
   "description": "Joomla CMS",
   "license": "GPL-2.0-or-later",
   "assets": [
+    {
+      "name": "com_templates.admin-template-compare.es5",
+      "type": "script",
+      "uri": "com_templates/admin-template-compare-es5.min.js",
+      "dependencies": [
+        "core",
+        "diff"
+      ],
+      "attributes": {
+        "nomodule": true,
+        "defer": true
+      }
+    },
+    {
+      "name": "com_templates.admin-template-compare",
+      "type": "script",
+      "uri": "com_templates/admin-template-compare.min.js",
+      "dependencies": [
+        "com_templates.admin-template-compare.es5"
+      ],
+      "attributes": {
+        "type": "module"
+      }
+    },
     {
       "name": "com_templates.admin-template-toggle-assignment.es5",
       "type": "script",
diff --git a/build/media_source/com_templates/js/admin-template-compare.es6.js b/build/media_source/com_templates/js/admin-template-compare.es6.js
new file mode 100644
index 0000000000000..8a1c3db0a2339
--- /dev/null
+++ b/build/media_source/com_templates/js/admin-template-compare.es6.js
@@ -0,0 +1,63 @@
+/**
+ * @copyright  (C) 2018 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license    GNU General Public License version 2 or later; see LICENSE.txt
+ *
+ * @deprecated  This file is deprecated and will be removed with Joomla 5.0
+ */
+(() => {
+  'use strict';
+
+  document.addEventListener('DOMContentLoaded', () => {
+    const decodeHtmlspecialChars = (text) => {
+      const map = {
+        '&amp;': '&',
+        '&#038;': '&',
+        '&lt;': '<',
+        '&gt;': '>',
+        '&quot;': '"',
+        '&#039;': "'",
+        '&#8217;': '’',
+        '&#8216;': '‘',
+        '&#8211;': '–',
+        '&#8212;': '—',
+        '&#8230;': '…',
+        '&#8221;': '”',
+      };
+
+      /* eslint-disable */
+      return text.replace(/\&[\w\d\#]{2,5}\;/g, (m) => { const n = map[m]; return n; });
+    };
+
+    const compare = (original, changed) => {
+      const display = changed.nextElementSibling;
+      let color = '';
+      let pre = null;
+      const diff = Diff.diffLines(original.innerHTML, changed.innerHTML);
+      const fragment = document.createDocumentFragment();
+
+      /* eslint-enable */
+
+      diff.forEach((part) => {
+        if (part.added) {
+          color = '#a6f3a6';
+        } else if (part.removed) {
+          color = '#f8cbcb';
+        } else {
+          color = '';
+        }
+        pre = document.createElement('pre');
+        pre.style.backgroundColor = color;
+        pre.className = 'diffview';
+        pre.appendChild(document.createTextNode(decodeHtmlspecialChars(part.value)));
+        fragment.appendChild(pre);
+      });
+
+      display.appendChild(fragment);
+    };
+
+    const diffs = [].slice.call(document.querySelectorAll('#original'));
+    for (let i = 0, l = diffs.length; i < l; i += 1) {
+      compare(diffs[i], diffs[i].nextElementSibling);
+    }
+  });
+})();
diff --git a/build/media_source/com_users/js/admin-users-mail.es6.js b/build/media_source/com_users/js/admin-users-mail.es6.js
new file mode 100644
index 0000000000000..ac12fcee51984
--- /dev/null
+++ b/build/media_source/com_users/js/admin-users-mail.es6.js
@@ -0,0 +1,36 @@
+/**
+ * @copyright   (C) 2018 Open Source Matters, Inc. <https://www.joomla.org>
+ * @license     GNU General Public License version 2 or later; see LICENSE.txt
+ *
+ * @deprecated  This file is deprecated and will be removed with Joomla 5.0
+ */
+
+(() => {
+  'use strict';
+
+  document.addEventListener('DOMContentLoaded', () => {
+    Joomla.submitbutton = (pressbutton) => {
+      const form = document.adminForm;
+      const html = document.createElement('joomla-alert');
+
+      if (pressbutton === 'mail.cancel') {
+        Joomla.submitform(pressbutton);
+        return;
+      }
+
+      // do field validation
+      if (form.jform_subject.value === '') {
+        html.innerText = Joomla.Text._('COM_USERS_MAIL_PLEASE_FILL_IN_THE_SUBJECT');
+        form.insertAdjacentElement('afterbegin', html);
+      } else if (form.jform_group.value < 0) {
+        html.innerText = Joomla.Text._('COM_USERS_MAIL_PLEASE_SELECT_A_GROUP');
+        form.insertAdjacentElement('afterbegin', html);
+      } else if (form.jform_message.value === '') {
+        html.innerText = Joomla.Text._('COM_USERS_MAIL_PLEASE_FILL_IN_THE_MESSAGE');
+        form.insertAdjacentElement('afterbegin', html);
+      } else {
+        Joomla.submitform(pressbutton);
+      }
+    };
+  });
+})();