diff --git a/core/modules/system/src/Controller/SystemController.php b/core/modules/system/src/Controller/SystemController.php
index 73180a0..a52f57b 100644
--- a/core/modules/system/src/Controller/SystemController.php
+++ b/core/modules/system/src/Controller/SystemController.php
@@ -218,8 +218,8 @@ public function themesPage() {
         if (isset($themes[$theme_key]) && file_exists($themes[$theme_key]->info['screenshot'])) {
           $theme->screenshot = array(
             'uri' => $themes[$theme_key]->info['screenshot'],
-            'alt' => $this->t('Screenshot for !theme theme', array('!theme' => $theme->info['name'])),
-            'title' => $this->t('Screenshot for !theme theme', array('!theme' => $theme->info['name'])),
+            'alt' => $this->t('Screenshot for @theme theme', array('@theme' => $theme->info['name'])),
+            'title' => $this->t('Screenshot for @theme theme', array('@theme' => $theme->info['name'])),
             'attributes' => array('class' => array('screenshot')),
           );
           break;
diff --git a/core/modules/system/src/Form/ModulesListForm.php b/core/modules/system/src/Form/ModulesListForm.php
index 2e80482..5b9d577 100644
--- a/core/modules/system/src/Form/ModulesListForm.php
+++ b/core/modules/system/src/Form/ModulesListForm.php
@@ -168,7 +168,7 @@ public function getFormId() {
    */
   public function buildForm(array $form, FormStateInterface $form_state) {
     require_once DRUPAL_ROOT . '/core/includes/install.inc';
-    $distribution = String::checkPlain(drupal_install_profile_distribution_name());
+    $distribution = Xss::filter(drupal_install_profile_distribution_name());
 
     // Include system.admin.inc so we can use the sort callbacks.
     $this->moduleHandler->loadInclude('system', 'inc', 'system.admin');
@@ -210,7 +210,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
     foreach (Element::children($form['modules']) as $package) {
       $form['modules'][$package] += array(
         '#type' => 'details',
-        '#title' => $this->t($package),
+        '#title' => Xss::filter($this->t($package)),
         '#open' => TRUE,
         '#theme' => 'system_modules_details',
         '#header' => array(
@@ -261,9 +261,9 @@ protected function buildRow(array $modules, Extension $module, $distribution) {
     $row['#requires'] = array();
     $row['#required_by'] = array();
 
-    $row['name']['#markup'] = $module->info['name'];
-    $row['description']['#markup'] = $this->t($module->info['description']);
-    $row['version']['#markup'] = $module->info['version'];
+    $row['name']['#markup'] = Xss::filter($module->info['name']);
+    $row['description']['#markup'] = Xss::filter($this->t($module->info['description']));
+    $row['version']['#markup'] = Xss::filter($module->info['version']);
 
     // Generate link for module's help page, if there is one.
     $row['links']['help'] = array();
@@ -338,7 +338,7 @@ protected function buildRow(array $modules, Extension $module, $distribution) {
     if (!empty($module->info['required'])) {
       // Used when displaying modules that are required by the installation profile
       $row['enable']['#disabled'] = TRUE;
-      $row['#required_by'][] = $distribution . (!empty($module->info['explanation']) ? ' ('. $module->info['explanation'] .')' : '');
+      $row['#required_by'][] = Xss::filter($distribution . (!empty($module->info['explanation']) ? ' ('. $module->info['explanation'] .')' : ''));
     }
 
     // Check the compatibilities.
diff --git a/sites/all/libraries/README.txt b/sites/all/libraries/README.txt
deleted file mode 100644
index 6f06b7c..0000000
--- a/sites/all/libraries/README.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-This directory should be used to place downloaded and custom libraries
-which are used by contributed modules. This will allow you to more 
-easily install Drupal contributed modules.