link and shortcut have baseFieldDefinition settings that do not do anything: default_value max_length

from #2406749: Use a link field for custom menu link it added in

MenuLinkContent

+    $fields['link'] = BaseFieldDefinition::create('link')
+      ->setLabel(t('Link'))
+      ->setDescription(t('The location this menu link points to.'))
+      ->setRequired(TRUE)
+      ->setSettings(array(
+        'default_value' => '',
+        'max_length' => 560,
+        'link_type' => LinkItemInterface::LINK_GENERIC,
+        'title' => DRUPAL_DISABLED,
+      ))
+    ;

but in

LinkItem

  public static function defaultFieldSettings() {
    return array(
      'title' => DRUPAL_OPTIONAL,
      'link_type' => LinkItemInterface::LINK_GENERIC
    ) + parent::defaultFieldSettings();
  }

expects title, link_type but not default_value or max_length

(FieldItemBase, the parent returns empty array)

  public static function defaultFieldSettings() {
    return array();
  }

grepping (ag):

$ ag "'max_length' => 560,"
core/modules/menu_link_content/src/Entity/MenuLinkContent.php
290:        'max_length' => 560,

core/modules/shortcut/src/Entity/Shortcut.php
155:        'max_length' => 560,

gives a clue that this code was copied from Shortcut