diff -u b/core/includes/bootstrap.inc b/core/includes/bootstrap.inc
--- b/core/includes/bootstrap.inc
+++ b/core/includes/bootstrap.inc
@@ -2056,8 +2056,9 @@
     list(, $prefix, $time, $salt, $hmac) = $matches;
     $check_string =  $prefix . ';' . $time . ';' . $salt;
     // We use the salt from settings.php to make the HMAC key, since
-    // the database is not yet initialized and we can't access any Drupal variables.
-    // The file properties add more entropy not easily accessible to others.
+    // the database is not yet initialized and we can't access the configuration
+    // system. The file properties add more entropy not easily accessible to
+    // others.
     $key = drupal_get_hash_salt() . filectime(__FILE__) . fileinode(__FILE__);
     $time_diff = REQUEST_TIME - $time;
     // We can't use Crypt::hmacBase64() yet because this can be called in very
@@ -2122,8 +2123,9 @@
 
   if (!isset($key)) {
     // We use the salt from settings.php to make the HMAC key, since
-    // the database is not yet initialized and we can't access any Drupal variables.
-    // The file properties add more entropy not easily accessible to others.
+    // the database is not yet initialized and we can't access the configuration
+    // system. The file properties add more entropy not easily accessible to
+    // others.
     $key = drupal_get_hash_salt() . filectime(__FILE__) . fileinode(__FILE__);
   }
   // Generate a moderately secure HMAC based on the database credentials.
reverted:
--- b/core/lib/Drupal/Core/EventSubscriber/ConfigGlobalOverrideSubscriber.php
+++ a/core/lib/Drupal/Core/EventSubscriber/ConfigGlobalOverrideSubscriber.php
@@ -23,7 +23,6 @@
    *   The Event to process.
    */
   public function configInit(ConfigEvent $event) {
-    // @todo global $config, https://drupal.org/node/1881582
     global $conf;
 
     $config = $event->getConfig();
diff -u b/core/modules/system/system.install b/core/modules/system/system.install
--- b/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -973,7 +973,7 @@
   );
 
   $schema['semaphore'] = array(
-    'description' => 'Table for holding semaphores, locks, flags, etc. that cannot be stored as Drupal variables since they must not be cached.',
+    'description' => 'Table for holding semaphores, locks, flags, etc. that cannot be stored as state since they must not be cached.',
     'fields' => array(
       'name' => array(
         'description' => 'Primary Key: Unique name.',
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Mail/PhpMail.php
+++ b/core/lib/Drupal/Core/Mail/PhpMail.php
@@ -33,7 +33,7 @@ public function format(array $message) {
   }
 
   /**
-   * Sends an e-mail message, using Drupal variables and default settings.
+   * Sends an e-mail message.
    *
    * @param array $message
    *   A message array, as described in hook_mail_alter().