diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index fea4464..a34a242 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -693,6 +693,8 @@ function _theme_build_registry($theme, $base_theme, $theme_engine) {
  *     the themes' machine names, and the values are the themes' human-readable
  *     names. This element is not set if there are no themes on the system that
  *     declare this theme as their base theme.
+ *
+ * @deprecated as of Drupal 8.0. Use \Drupal::service('theme_handler')->listInfo().
  */
 function list_themes($refresh = FALSE) {
   /** @var \Drupal\Core\Theme\ThemeHandler $theme_handler */
@@ -720,6 +722,8 @@ function list_themes($refresh = FALSE) {
  * @return
  *   Returns an array of all of the theme's ancestors; the first element's value
  *   will be NULL if an error occurred.
+ *
+ * @deprecated as of Drupal 8.0. Use \Drupal::service('theme_handler')->getBaseThemes().
  */
 function drupal_find_base_themes($themes, $key) {
   return \Drupal::service('theme_handler')->getBaseThemes($themes, $key);
@@ -1410,6 +1414,8 @@ function theme_settings_convert_to_config(array $theme_settings, Config $config)
  *
  * @param $theme_list
  *   An array of theme names.
+ *
+ * @deprecated as of Drupal 8.0. Use \Drupal::service('theme_handler')->enable().
  */
 function theme_enable($theme_list) {
   \Drupal::service('theme_handler')->enable($theme_list);
@@ -1420,6 +1426,8 @@ function theme_enable($theme_list) {
  *
  * @param $theme_list
  *   An array of theme names.
+ *
+ * @deprecated as of Drupal 8.0. Use \Drupal::service('theme_handler')->disable().
  */
 function theme_disable($theme_list) {
   \Drupal::service('theme_handler')->disable($theme_list);
diff --git a/core/lib/Drupal/Core/Theme/ThemeHandler.php b/core/lib/Drupal/Core/Theme/ThemeHandler.php
index 8adea15..d668eb7 100644
--- a/core/lib/Drupal/Core/Theme/ThemeHandler.php
+++ b/core/lib/Drupal/Core/Theme/ThemeHandler.php
@@ -13,7 +13,6 @@
 use Drupal\Core\Extension\ExtensionNameLengthException;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Routing\RouteBuilder;
-use Drupal\Core\SystemListing;
 use Drupal\Core\SystemListingInfo;
 use Drupal\Core\Extension\InfoParserInterface;
 
@@ -39,6 +38,11 @@ class ThemeHandler implements ThemeHandlerInterface {
     'secondary_menu',
   );
 
+  /**
+   * A list of all currently available themes.
+   *
+   * @var array
+   */
   protected $list = array();
 
   /**
@@ -178,8 +182,7 @@ public function disable(array $theme_list) {
   public function listInfo() {
     if (empty($this->list)) {
       $this->list = array();
-      // Extract from the database only when it is available.
-      // Also check that the site is not in the middle of an install or update.
+      // Check that the site is not in the middle of an install or update.
       if (!defined('MAINTENANCE_MODE')) {
         try {
           $themes = $this->systemThemeList();