diff --git a/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
index 8ec2539..a0dab7f 100644
--- a/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -897,7 +897,7 @@ function drupal_get_filename($type, $name, $filename = NULL) {
         }
       }
       catch (Exception $e) {
-        // The keyvalue service raise an exception due because the backend might
+        // The keyvalue service raised an exception because the backend might
         // be down. We have a fallback for this case so we hide the error
         // completely.
       }
@@ -905,7 +905,7 @@ function drupal_get_filename($type, $name, $filename = NULL) {
     // Fallback to searching the filesystem if the database could not find the
     // file or the file returned by the database is not found.
     if (!isset($files[$type][$name])) {
-      // We have a consistent directory naming: modules, themes...
+      // We have consistent directory naming: modules, themes...
       $dir = $type . 's';
       if ($type == 'theme_engine') {
         $dir = 'themes/engines';
@@ -2461,7 +2461,7 @@ function drupal_container(Container $new_container = NULL, $rebuild = FALSE) {
       ->register('config.storage.staging', 'Drupal\Core\Config\FileStorage')
       ->addArgument(config_get_config_directory(CONFIG_STAGING_DIRECTORY));
 
-    // KeyValueStore.
+    // Register the KeyValueStore factory.
     $container
       ->register('keyvalue', 'Drupal\Core\KeyValueStore\KeyValueFactory');
   }
@@ -2500,7 +2500,8 @@ function typed_data() {
  * Returns the test prefix if this is an internal request from SimpleTest.
  *
  * @param string $new_prefix
- *   Internal use only. A new prefix to be stored.
+ *   Internal use only. A new prefix to be stored. Passed in by tests that use
+ *   the test runner from within a test.
  *
  * @return
  *   Either the simpletest prefix (the string "simpletest" followed by any
diff --git a/core/includes/install.inc b/core/includes/install.inc
index d0ecbae..db92987 100644
--- a/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -415,7 +415,6 @@ function drupal_install_system() {
     ->get('system.schema')
     ->set('system', $system_version);
 
-  // Enable System module.
   // System module needs to be enabled and the system/module lists need to be
   // reset first in order to allow config_install_default_config() to invoke
   // config import callbacks.
diff --git a/core/includes/module.inc b/core/includes/module.inc
index ecf2fcf..00d4d1a 100644
--- a/core/includes/module.inc
+++ b/core/includes/module.inc
@@ -197,16 +197,16 @@ function system_list($type) {
 
       // Build a list of themes.
       $enabled_themes = config('system.theme')->get('enabled');
-      //$theme_files = state()->get('system.theme.files');
       // @todo Themes include all themes, including disabled/uninstalled. This
       //   system.theme.data state will go away entirely as soon as themes have
       //   a proper installation status.
       // @see http://drupal.org/node/1067408
       $theme_data = state()->get('system.theme.data');
       if (empty($theme_data)) {
-        // system_list() may be called from _drupal_bootstrap_code() and
+        // @todo: system_list() may be called from _drupal_bootstrap_code() and
         // module_load_all(), in which case system.module is not loaded yet.
         // Prevent a filesystem scan in drupal_load() and include it directly.
+        // @see http://drupal.org/node/1067408
         require_once DRUPAL_ROOT . '/core/modules/system/system.module';
         $theme_data = system_rebuild_theme_data();
       }
@@ -489,6 +489,7 @@ function module_enable($module_list, $enable_dependencies = TRUE) {
       $enabled = FALSE;
       $weight = $disabled_config->get($module);
     }
     if (!$enabled) {
       $module_config
         ->set("enabled.$module", $weight)
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 5080a20..bb3f2b4 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -2991,8 +2991,8 @@ function system_rebuild_theme_data() {
   //   a theme, but various other functions expect it to return themes with a
   //   $status property. system_list() stores the return value of this function
   //   in state, and ensures to set/override the $status property for each theme
-  //   based on the current config. Remove this code here when themes have a
-  //   proper installation status.
+  //   based on the current config. Remove this code when themes have a proper
+  //   installation status.
   // @see http://drupal.org/node/1067408
   $enabled_themes = config('system.theme')->get('enabled');
   $files = array();