diff --git a/core/lib/Drupal/Core/EventSubscriber/ExceptionTestSiteSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/ExceptionTestSiteSubscriber.php
index a091b4e..8cbf03c 100644
--- a/core/lib/Drupal/Core/EventSubscriber/ExceptionTestSiteSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/ExceptionTestSiteSubscriber.php
@@ -91,7 +91,7 @@ public static function getSubscribedEvents() {
   }
 
   /**
-   * Returns if headers should be added.
+   * Indicates whether headers should be added.
    *
    * @return bool
    *   TRUE if headers should be added.
diff --git a/core/modules/simpletest/src/Tests/BrokenSetUpTest.php b/core/modules/simpletest/src/Tests/BrokenSetUpTest.php
index ed75433..428b7e9 100644
--- a/core/modules/simpletest/src/Tests/BrokenSetUpTest.php
+++ b/core/modules/simpletest/src/Tests/BrokenSetUpTest.php
@@ -30,7 +30,7 @@ class BrokenSetUpTest extends WebTestBase {
   public static $modules = array('simpletest');
 
   /**
-   * The memory limit for this test, the Simpletest UI is very expensive.
+   * Set no memory limit for this test. The SimpleTest UI is very expensive.
    */
   protected $memoryUsageTrigger = FALSE;
 
diff --git a/core/modules/simpletest/src/Tests/InstallationProfileModuleTestsTest.php b/core/modules/simpletest/src/Tests/InstallationProfileModuleTestsTest.php
index 561d2f4..ed4afab 100644
--- a/core/modules/simpletest/src/Tests/InstallationProfileModuleTestsTest.php
+++ b/core/modules/simpletest/src/Tests/InstallationProfileModuleTestsTest.php
@@ -31,7 +31,7 @@ class InstallationProfileModuleTestsTest extends WebTestBase {
   protected $adminUser;
 
   /**
-   * The memory limit for this test, the Simpletest UI is very expensive.
+   * Set no memory limit for this test. The SimpleTest UI is very expensive.
    */
   protected $memoryUsageTrigger = FALSE;
 
diff --git a/core/modules/simpletest/src/Tests/MissingCheckedRequirementsTest.php b/core/modules/simpletest/src/Tests/MissingCheckedRequirementsTest.php
index f9364b3..9e099d2 100644
--- a/core/modules/simpletest/src/Tests/MissingCheckedRequirementsTest.php
+++ b/core/modules/simpletest/src/Tests/MissingCheckedRequirementsTest.php
@@ -24,7 +24,7 @@ class MissingCheckedRequirementsTest extends WebTestBase {
   public static $modules = array('simpletest');
 
   /**
-   * The memory limit for this test, the Simpletest UI is very expensive.
+   * Set no memory limit for this test. The SimpleTest UI is very expensive.
    */
   protected $memoryUsageTrigger = FALSE;
 
diff --git a/core/modules/simpletest/src/Tests/OtherInstallationProfileTestsTest.php b/core/modules/simpletest/src/Tests/OtherInstallationProfileTestsTest.php
index 6d1c625..9d03383 100644
--- a/core/modules/simpletest/src/Tests/OtherInstallationProfileTestsTest.php
+++ b/core/modules/simpletest/src/Tests/OtherInstallationProfileTestsTest.php
@@ -39,7 +39,7 @@ class OtherInstallationProfileTestsTest extends WebTestBase {
   protected $profile = 'minimal';
 
   /**
-   * The memory limit for this test, the Simpletest UI is very expensive.
+   * Set no memory limit for this test. The SimpleTest UI is very expensive.
    */
   protected $memoryUsageTrigger = FALSE;
 
diff --git a/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php b/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php
index 80c4032..c974498 100644
--- a/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php
+++ b/core/modules/simpletest/src/Tests/SimpleTestBrowserTest.php
@@ -25,7 +25,7 @@ class SimpleTestBrowserTest extends WebTestBase {
   public static $modules = array('simpletest', 'test_page_test');
 
   /**
-   * The memory limit for this test, the Simpletest UI is very expensive.
+   * Set no memory limit for this test. The SimpleTest UI is very expensive.
    */
   protected $memoryUsageTrigger = FALSE;
 
diff --git a/core/modules/simpletest/src/Tests/SimpleTestTest.php b/core/modules/simpletest/src/Tests/SimpleTestTest.php
index 3166123..ba8c3be 100644
--- a/core/modules/simpletest/src/Tests/SimpleTestTest.php
+++ b/core/modules/simpletest/src/Tests/SimpleTestTest.php
@@ -29,7 +29,7 @@ class SimpleTestTest extends WebTestBase {
   public static $modules = array('simpletest', 'test_page_test');
 
   /**
-   * The memory limit for this test, the Simpletest UI is very expensive.
+   * Set no memory limit for this test. The SimpleTest UI is very expensive.
    */
   protected $memoryUsageTrigger = FALSE;
 
diff --git a/core/modules/simpletest/src/WebTestBase.php b/core/modules/simpletest/src/WebTestBase.php
index d350006..b6750cb 100644
--- a/core/modules/simpletest/src/WebTestBase.php
+++ b/core/modules/simpletest/src/WebTestBase.php
@@ -63,14 +63,14 @@
   protected $url;
 
   /**
-   * Set to the maximum number of MB of memory usage to allow on the child site.
+   * The maximum memory usage to allow on the child site, in MB.
    *
    * The minimum amount of memory Drupal expects to have available is defined by
-   * DRUPAL_MINIMUM_PHP_MEMORY_LIMIT. This value should either be equal or less
-   * to DRUPAL_MINIMUM_PHP_MEMORY_LIMIT. If a module requires more memory than
-   * this the module should add a check to its hook_requirements and use the
-   * higher value in it's tests. The check can be disabled for a specific test
-   * by setting it to FALSE.
+   * DRUPAL_MINIMUM_PHP_MEMORY_LIMIT. This default value on the base class
+   * should be less than or equal to DRUPAL_MINIMUM_PHP_MEMORY_LIMIT. If a
+   * module requires more memory than this limit, the module should add a
+   * check to its hook_requirements() and use the higher value in its tests.
+   * The check can be disabled for a specific test by setting it to FALSE.
    *
    * @var string|FALSE
    */