diff --git a/core/includes/install.inc b/core/includes/install.inc
index b778e30..e0890a1 100644
--- a/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -209,7 +209,7 @@ function drupal_rewrite_settings($settings = array(), $settings_file = NULL) {
   }
   $contents = file_get_contents(DRUPAL_ROOT . '/' . $settings_file);
   if ($contents !== FALSE) {
-    // Append PHP tag if the settings.php file is empty.
+    // Initialize the contents for the settings.php file if it is empty.
     if ($contents == '') {
       $contents = "<?php\n";
     }
diff --git a/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php b/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php
index dbc6442..747cfea 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/SettingsRewriteTest.php
@@ -111,6 +111,7 @@ function testDrupalRewriteSettings() {
     }
 
     // Test that <?php gets added to the start of an empty settings file.
+    // Set the array of settings that will be written to the file.
     $test = array(
       'settings' => array(
         'no_index_value_scalar' => (object) array(
@@ -121,9 +122,12 @@ function testDrupalRewriteSettings() {
       ),
       'expected' => '$no_index_value_scalar = false; // comment'
     );
+    // Make an empty file.
     $filename = variable_get('file_public_path', conf_path() . '/files') . '/empty_settings.php';
     file_put_contents(DRUPAL_ROOT . '/' . $filename, "");
+    // Write the setting to the file.
     drupal_rewrite_settings($test['settings'], $filename);
+    // Check that the result is just the php opening tag and the settings.
     $this->assertEqual(file_get_contents(DRUPAL_ROOT . '/' . $filename), "<?php\n" . $test['expected'] . "\n");
   }
 }