reverted:
--- b/core/modules/options/options.module
+++ a/core/modules/options/options.module
@@ -44,7 +44,7 @@
       'description' => t("This field stores integer values from a list of allowed 'value => label' pairs, i.e. 'Lifetime in days': 1 => 1 day, 7 => 1 week, 31 => 1 month."),
       'settings' => array('allowed_values' => array(), 'allowed_values_function' => ''),
       'default_widget' => 'options_select',
+      'default_formatter' => 'list_default',
-      'default_formatter' => 'options_list_default',
       'field item class' => '\Drupal\number\Type\IntegerItem',
     ),
     'list_float' => array(
@@ -52,7 +52,7 @@
       'description' => t("This field stores float values from a list of allowed 'value => label' pairs, i.e. 'Fraction': 0 => 0, .25 => 1/4, .75 => 3/4, 1 => 1."),
       'settings' => array('allowed_values' => array(), 'allowed_values_function' => ''),
       'default_widget' => 'options_select',
+      'default_formatter' => 'list_default',
-      'default_formatter' => 'options_list_default',
       'field item class' => '\Drupal\number\Type\FloatItem',
     ),
     'list_text' => array(
@@ -60,7 +60,7 @@
       'description' => t("This field stores text values from a list of allowed 'value => label' pairs, i.e. 'US States': IL => Illinois, IA => Iowa, IN => Indiana."),
       'settings' => array('allowed_values' => array(), 'allowed_values_function' => ''),
       'default_widget' => 'options_select',
+      'default_formatter' => 'list_default',
-      'default_formatter' => 'options_list_default',
       'field item class' => '\Drupal\text\Type\TextItem',
     ),
     'list_boolean' => array(
@@ -68,7 +68,7 @@
       'description' => t('This field stores simple on/off or yes/no options.'),
       'settings' => array('allowed_values' => array(), 'allowed_values_function' => ''),
       'default_widget' => 'options_buttons',
+      'default_formatter' => 'list_default',
-      'default_formatter' => 'options_list_default',
       'field item class' => '\Drupal\number\Type\IntegerItem',
     ),
   );
only in patch2:
unchanged:
--- a/core/modules/options/lib/Drupal/options/Plugin/field/formatter/OptionsDefaultFormatter.php
+++ b/core/modules/options/lib/Drupal/options/Plugin/field/formatter/OptionsDefaultFormatter.php
@@ -16,7 +16,7 @@
  * Plugin implementation of the 'list_default' formatter.
  *
  * @Plugin(
- *   id = "options_list_default",
+ *   id = "list_default",
  *   module = "options",
  *   label = @Translation("Default"),
  *   field_types = {
only in patch2:
unchanged:
--- a/core/modules/options/lib/Drupal/options/Plugin/field/formatter/OptionsKeyFormatter.php
+++ b/core/modules/options/lib/Drupal/options/Plugin/field/formatter/OptionsKeyFormatter.php
@@ -16,7 +16,7 @@
  * Plugin implementation of the 'list_key' formatter.
  *
  * @Plugin(
- *   id = "options_list_key",
+ *   id = "list_key",
  *   module = "options",
  *   label = @Translation("Key"),
  *   field_types = {
only in patch2:
unchanged:
--- a/core/modules/options/lib/Drupal/options/Tests/OptionsFieldUITest.php
+++ b/core/modules/options/lib/Drupal/options/Tests/OptionsFieldUITest.php
@@ -321,7 +321,7 @@ function testNodeDisplay() {
     $this->drupalPost('node/' . $node->nid . '/edit', $edit, t('Save and keep published'));
 
     // Check the node page and see if the values are correct.
-    $file_formatters = array('options_list_default', 'options_list_key');
+    $file_formatters = array('list_default', 'list_key');
     foreach ($file_formatters as $formatter) {
       $edit = array(
         "fields[$this->field_name][type]" => $formatter,
@@ -329,7 +329,7 @@ function testNodeDisplay() {
       $this->drupalPost('admin/structure/types/manage/' . $this->type_name . '/display', $edit, t('Save'));
       $this->drupalGet('node/' . $node->nid);
 
-      if ($formatter == 'options_list_default') {
+      if ($formatter == 'list_default') {
         $output = $on;
       }
       else {