diff -u b/core/lib/Drupal/Core/Field/WidgetBase.php b/core/lib/Drupal/Core/Field/WidgetBase.php
--- b/core/lib/Drupal/Core/Field/WidgetBase.php
+++ b/core/lib/Drupal/Core/Field/WidgetBase.php
@@ -211,13 +211,13 @@
             ];
           }
 
-          $element['_remove'] = array(
+          $element['_remove'] = [
             '#title' => $this->t('Remove'),
             '#title_display' => 'invisible',
             '#type' => 'checkbox',
             '#default_value' => $items[$delta]->_remove ?: FALSE,
             '#weight' => 101,
-          );
+          ];
         }
 
         $elements[$delta] = $element;
@@ -369,7 +369,7 @@
         // Remove the 'value' of the 'add more' button.
         unset($values['add_more']);
 
-        // Filter out removed items
+        // Filter out removed items.
         foreach ($values as $delta => $value) {
           if (!empty($value['_remove'])) unset($values[$delta]);
         }