diff --git a/core/modules/field/tests/src/Kernel/EntityReference/Views/EntityReferenceRelationshipTest.php b/core/modules/field/tests/src/Kernel/EntityReference/Views/EntityReferenceRelationshipTest.php
index 1b4ce03..d18d9f3 100644
--- a/core/modules/field/tests/src/Kernel/EntityReference/Views/EntityReferenceRelationshipTest.php
+++ b/core/modules/field/tests/src/Kernel/EntityReference/Views/EntityReferenceRelationshipTest.php
@@ -281,6 +281,9 @@ public function testDataTableRelationshipWithLongFieldName() {
     }
   }
 
+  /**
+   * Tests group by with optional and empty relationship.
+   */
   public function testGroupByWithEmptyRelationships() {
     $entities = [];
     // Create 4 entities with name1 and 3 entities with name2.
@@ -321,9 +324,12 @@ public function testGroupByWithEmptyRelationships() {
     $view = Views::getView('test_entity_reference_group_by_empty_relationships');
     $this->executeView($view);
     $this->assertCount(4, $view->result);
+    // First three results should contain a reference from EntityTestMul.
     $this->assertNotEmpty($view->getStyle()->getField(0, 'name_2'));
     $this->assertNotEmpty($view->getStyle()->getField(1, 'name_2'));
     $this->assertNotEmpty($view->getStyle()->getField(2, 'name_2'));
+    // Fourth result has no reference from EntityTestMul hence the output for
+    // should be empty.
     $this->assertEqual('', $view->getStyle()->getField(3, 'name_2'));
   }
 
diff --git a/core/modules/views/src/Plugin/views/field/Field.php b/core/modules/views/src/Plugin/views/field/Field.php
index 8eb3b5c..eccaf48 100644
--- a/core/modules/views/src/Plugin/views/field/Field.php
+++ b/core/modules/views/src/Plugin/views/field/Field.php
@@ -820,7 +820,7 @@ public function getItems(ResultRow $values) {
         'settings' => $this->options['settings'],
         'label' => 'hidden',
       ];
-      // optional relationships do not provide an entity at all. So we can't use
+      // Optional relationships may not provide an entity at all. So we can't use
       // createEntityForGroupBy() for those rows.
       if (($entity = $this->getEntity($values)) && ($entity = $this->createEntityForGroupBy($entity, $values))) {
         // Some bundles might not have a specific field, in which case the faked