diff --git a/core/lib/Drupal/Core/Theme/Registry.php b/core/lib/Drupal/Core/Theme/Registry.php
index 72ef9ac..9459bef 100644
--- a/core/lib/Drupal/Core/Theme/Registry.php
+++ b/core/lib/Drupal/Core/Theme/Registry.php
@@ -476,9 +476,9 @@ protected function processExtension(array &$cache, $name, $type, $theme, $path)
         }
 
         // Check for the override flag and prevent the cached variable
-        // preprocessors from being used. This allows themes or theme engines
-        // to remove variable preprocessors set earlier in the registry build.
-        // @todo
+        // preprocessors from being used. This allows themes or theme engines to
+        // remove variable preprocessors set earlier in the registry build.
+        // @todo check if caching is broken.
         if (!empty($info['override preprocess functions'])) {
           // Flag not needed inside the registry.
           unset($result[$hook]['override preprocess functions']);
diff --git a/core/lib/Drupal/Core/Theme/ThemeManager.php b/core/lib/Drupal/Core/Theme/ThemeManager.php
index 45ee78a..122182b 100644
--- a/core/lib/Drupal/Core/Theme/ThemeManager.php
+++ b/core/lib/Drupal/Core/Theme/ThemeManager.php
@@ -387,9 +387,9 @@ protected function theme($hook, $variables = array()) {
   /**
    * Create a list of preprocess functions to be run for a single theme output.
    *
-   * @param $info
-   * @param $hook
-   * @param $suggesitons
+   * @param array $info
+   * @param array $hook
+   * @param array $suggesitons
    *
    */
   protected function buildPreprocess($info, $hook, $suggestions) {
@@ -406,8 +406,8 @@ protected function buildPreprocess($info, $hook, $suggestions) {
     // Default variable preprocessor prefix.
     $prefixes[] = 'template';
     // Add all modules so they can intervene with their own variable
-    // preprocessors. This allows them to provide variable preprocessors
-    // even if they are not the owner of the current hook.
+    // preprocessors. This allows them to provide variable preprocessors even
+    // if they are not the owner of the current hook.
     $prefixes = array_merge($prefixes, $module_list);
 
     foreach (array_reverse($theme->getBaseThemes()) as $base) {
@@ -433,8 +433,8 @@ protected function buildPreprocess($info, $hook, $suggestions) {
     $preprocess_functions = [];
     foreach (array_reverse($suggestions) as $suggestion) {
       foreach ($prefixes as $prefix) {
-        // Only use non-hook-specific variable preprocessors for theming
-        // hooks implemented as templates. See _theme().
+        // Only use non-hook-specific variable preprocessors for theming hooks
+        // implemented as templates. See _theme().
         if (isset($info['template']) && function_exists($prefix . '_preprocess')) {
           $preprocess_functions[] = $prefix . '_preprocess';
         }
diff --git a/core/modules/system/src/Tests/Theme/ThemeTest.php b/core/modules/system/src/Tests/Theme/ThemeTest.php
index 9289951..fba91cc 100644
--- a/core/modules/system/src/Tests/Theme/ThemeTest.php
+++ b/core/modules/system/src/Tests/Theme/ThemeTest.php
@@ -288,7 +288,8 @@ function testRegionClass() {
   }
 
   /**
-   * Ensures suggestion preprocess functions run even for default implementations.
+   * Ensures suggestion preprocess functions run even for default
+   * implementations.
    *
    * The theme hook used by this test has its base preprocess function in a
    * separate file, so this test also ensures that that file is correctly loaded