diff --git a/core/lib/Drupal/Core/Field/Annotation/FieldFormatter.php b/core/lib/Drupal/Core/Field/Annotation/FieldFormatter.php
index 067f54d4803a6f424023ed313062779ff6a18617..80d30257e6616a7f4447765d565e54b4f465f1b6 100644
--- a/core/lib/Drupal/Core/Field/Annotation/FieldFormatter.php
+++ b/core/lib/Drupal/Core/Field/Annotation/FieldFormatter.php
@@ -22,6 +22,8 @@
  *
  * @see \Drupal\Core\Field\FormatterPluginManager
  * @see \Drupal\Core\Field\FormatterInterface
+ *
+ * @ingroup field_formatter
  */
 class FieldFormatter extends Plugin {
 
diff --git a/core/lib/Drupal/Core/Field/Annotation/FieldType.php b/core/lib/Drupal/Core/Field/Annotation/FieldType.php
index 276cd0bf97c8e7283cc775a44ccc03a0e32190a1..d69f4a6b62709ea0ec16c347377a0a13e0dc365b 100644
--- a/core/lib/Drupal/Core/Field/Annotation/FieldType.php
+++ b/core/lib/Drupal/Core/Field/Annotation/FieldType.php
@@ -15,6 +15,8 @@
  * Additional annotation keys for field types can be defined in
  * hook_field_info_alter().
  *
+ * @ingroup field_types
+ *
  * @Annotation
  */
 class FieldType extends DataType {
diff --git a/core/lib/Drupal/Core/Field/Annotation/FieldWidget.php b/core/lib/Drupal/Core/Field/Annotation/FieldWidget.php
index 0f3535d13d0b187022952393c277cf66f96883d0..7e7d14d0489ace352689bf0fd74ad6918b003e8b 100644
--- a/core/lib/Drupal/Core/Field/Annotation/FieldWidget.php
+++ b/core/lib/Drupal/Core/Field/Annotation/FieldWidget.php
@@ -21,6 +21,8 @@
  *
  * @see \Drupal\Core\Field\WidgetPluginManager
  * @see \Drupal\Core\Field\WidgetInterface
+ *
+ * @ingroup field_widget
  */
 class FieldWidget extends Plugin {
 
diff --git a/core/lib/Drupal/Core/Field/FieldItemBase.php b/core/lib/Drupal/Core/Field/FieldItemBase.php
index 39b9412745f602b7d5bc97719ba7d49522350e0f..296c468210e5a4a98e303af7f8e502590634a583 100644
--- a/core/lib/Drupal/Core/Field/FieldItemBase.php
+++ b/core/lib/Drupal/Core/Field/FieldItemBase.php
@@ -20,6 +20,7 @@
  * the static method propertyDefinitions().
  *
  * @see \Drupal\Core\Field\FieldItemInterface
+ * @ingroup field_types
  */
 abstract class FieldItemBase extends Map implements FieldItemInterface {
 
diff --git a/core/lib/Drupal/Core/Field/FieldItemInterface.php b/core/lib/Drupal/Core/Field/FieldItemInterface.php
index cba5653e45a13bf91bbb48d8f2bf500d3c96015c..ee2799625da21a289f8275dd89d2fa889745404c 100644
--- a/core/lib/Drupal/Core/Field/FieldItemInterface.php
+++ b/core/lib/Drupal/Core/Field/FieldItemInterface.php
@@ -20,6 +20,7 @@
  *
  * @see \Drupal\Core\Field\FieldItemListInterface
  * @see \Drupal\Core\Field\FieldItemBase
+ * @ingroup field_types
  */
 interface FieldItemInterface extends ComplexDataInterface {
 
diff --git a/core/lib/Drupal/Core/Field/FieldTypePluginManager.php b/core/lib/Drupal/Core/Field/FieldTypePluginManager.php
index 9f64aaf0845e1282f01c374ca8e6ee17658e6f89..4b7faf73c405a49fb12600c2c7f17cfa74d30d8f 100644
--- a/core/lib/Drupal/Core/Field/FieldTypePluginManager.php
+++ b/core/lib/Drupal/Core/Field/FieldTypePluginManager.php
@@ -14,6 +14,8 @@
 
 /**
  * Plugin manager for 'field type' plugins.
+ *
+ * @ingroup field_types
  */
 class FieldTypePluginManager extends DefaultPluginManager implements FieldTypePluginManagerInterface {
 
diff --git a/core/lib/Drupal/Core/Field/FieldTypePluginManagerInterface.php b/core/lib/Drupal/Core/Field/FieldTypePluginManagerInterface.php
index f9883b8ce253a9b720d5ff727bda2a6372de4548..908ef0d17a0c703ab24b6021413bd78b94677bb2 100644
--- a/core/lib/Drupal/Core/Field/FieldTypePluginManagerInterface.php
+++ b/core/lib/Drupal/Core/Field/FieldTypePluginManagerInterface.php
@@ -11,6 +11,8 @@
 
 /**
  * Defines an interface for the field type plugin manager.
+ *
+ * @ingroup field_types
  */
 interface FieldTypePluginManagerInterface extends PluginManagerInterface {
 
diff --git a/core/lib/Drupal/Core/Field/FormatterBase.php b/core/lib/Drupal/Core/Field/FormatterBase.php
index bc3cdb653e2687c35830020e9e623c3b778468ee..ed309a9175d5e27912e1a562849297231d2aa457 100644
--- a/core/lib/Drupal/Core/Field/FormatterBase.php
+++ b/core/lib/Drupal/Core/Field/FormatterBase.php
@@ -9,6 +9,8 @@
 
 /**
  * Base class for 'Field formatter' plugin implementations.
+ *
+ * @ingroup field_formatter
  */
 abstract class FormatterBase extends PluginSettingsBase implements FormatterInterface {
 
diff --git a/core/lib/Drupal/Core/Field/FormatterInterface.php b/core/lib/Drupal/Core/Field/FormatterInterface.php
index fa633727024325804af06dc2ba70289d287dc408..9db98577ecee3ce5e225799ae59e4b1b54739023 100644
--- a/core/lib/Drupal/Core/Field/FormatterInterface.php
+++ b/core/lib/Drupal/Core/Field/FormatterInterface.php
@@ -8,7 +8,9 @@
 namespace Drupal\Core\Field;
 
 /**
- * Interface definition for field widget plugins.
+ * Interface definition for field formatter plugins.
+ *
+ * @ingroup field_formatter
  */
 interface FormatterInterface extends PluginSettingsInterface {
 
diff --git a/core/lib/Drupal/Core/Field/FormatterPluginManager.php b/core/lib/Drupal/Core/Field/FormatterPluginManager.php
index c16d23ff5a69fe7602570542fec84e54e0b50028..e8bba9c3b887a16abe817887a49c2cdb758c42f6 100644
--- a/core/lib/Drupal/Core/Field/FormatterPluginManager.php
+++ b/core/lib/Drupal/Core/Field/FormatterPluginManager.php
@@ -14,6 +14,8 @@
 
 /**
  * Plugin type manager for field formatters.
+ *
+ * @ingroup field_formatter
  */
 class FormatterPluginManager extends DefaultPluginManager {
 
diff --git a/core/lib/Drupal/Core/Field/WidgetBase.php b/core/lib/Drupal/Core/Field/WidgetBase.php
index fa61dd2c6e20b4ec16e2ac19a39fd292600b81a2..18602f47480677ff8a88568f649d545efce3e66e 100644
--- a/core/lib/Drupal/Core/Field/WidgetBase.php
+++ b/core/lib/Drupal/Core/Field/WidgetBase.php
@@ -15,6 +15,8 @@
 
 /**
  * Base class for 'Field widget' plugin implementations.
+ *
+ * @ingroup field_widget
  */
 abstract class WidgetBase extends PluginSettingsBase implements WidgetInterface {
 
diff --git a/core/lib/Drupal/Core/Field/WidgetInterface.php b/core/lib/Drupal/Core/Field/WidgetInterface.php
index a05f1d40ad1a19cb6728adb4009be8ffc593f7aa..1edfe4513db6101c8c3f341d726e7637f8642b3d 100644
--- a/core/lib/Drupal/Core/Field/WidgetInterface.php
+++ b/core/lib/Drupal/Core/Field/WidgetInterface.php
@@ -16,6 +16,8 @@
  * to override. See Drupal\Core\Field\WidgetBaseInterface for base
  * wrapping methods that should most likely be inherited directly from
  * Drupal\Core\Field\WidgetBase..
+ *
+ * @ingroup field_widget
  */
 interface WidgetInterface extends WidgetBaseInterface {
 
diff --git a/core/lib/Drupal/Core/Field/WidgetPluginManager.php b/core/lib/Drupal/Core/Field/WidgetPluginManager.php
index 7b58b6c148e49ee1cb685a842935b48a3bae3aee..2a0145f49f998ae011ab8832ec715350c81e34d2 100644
--- a/core/lib/Drupal/Core/Field/WidgetPluginManager.php
+++ b/core/lib/Drupal/Core/Field/WidgetPluginManager.php
@@ -14,6 +14,8 @@
 
 /**
  * Plugin type manager for field widgets.
+ *
+ * @ingroup field_widget
  */
 class WidgetPluginManager extends DefaultPluginManager {
 
diff --git a/core/modules/field/field.api.php b/core/modules/field/field.api.php
index c1c097e40063dc929227a144417384be7dcd2546..e8fb142970964b865a02bae587a0f762b26cffda 100644
--- a/core/modules/field/field.api.php
+++ b/core/modules/field/field.api.php
@@ -18,6 +18,15 @@
  * and so on. The data type(s) accepted by a field are defined in
  * hook_field_schema().
  *
+ * Field types are plugins annotated with class
+ * \Drupal\Core\Entity\Annotation\FieldType, and implement plugin interface
+ * \Drupal\Core\Field\FieldItemInterface. Field Type plugins are managed by the
+ * \Drupal\Core\Field\FieldTypePluginManager class. Field type classes usually
+ * extend base class \Drupal\Core\Field\FieldItemBase. Field-type plugins need
+ * to be in the namespace \Drupal\{your_module}\Plugin\Field\FieldType. See the
+ * @link plugin_api Plugin API topic @endlink for more information on how to
+ * define plugins.
+ *
  * The Field Types API also defines two kinds of pluggable handlers: widgets
  * and formatters. @link field_widget Widgets @endlink specify how the field
  * appears in edit forms, while @link field_formatter formatters @endlink
@@ -25,6 +34,11 @@
  *
  * See @link field Field API @endlink for information about the other parts of
  * the Field API.
+ *
+ * @see field
+ * @see field_widget
+ * @see field_formatter
+ * @see plugin_api
  */
 
 
@@ -57,11 +71,11 @@ function hook_field_info_alter(&$info) {
  * which widget to use.
  *
  * Widgets are Plugins managed by the
- * Drupal\Core\Field\WidgetPluginManager class. A widget is
- * implemented by providing a class that implements
- * Drupal\Core\Field\WidgetInterface (in most cases, by
- * subclassing Drupal\Core\Field\WidgetBase), and provides the
- * proper annotation block.
+ * \Drupal\Core\Field\WidgetPluginManager class. A widget is a plugin annotated
+ * with class \Drupal\Core\Entity\Annotation\FieldWidget that implements
+ * \Drupal\Core\Field\WidgetInterface (in most cases, by
+ * subclassing \Drupal\Core\Field\WidgetBase). Widget plugins need to be in the
+ * namespace \Drupal\{your_module}\Plugin\Field\FieldWidget.
  *
  * Widgets are @link forms_api_reference.html Form API @endlink
  * elements with additional processing capabilities. The methods of the
@@ -71,6 +85,7 @@ function hook_field_info_alter(&$info) {
  * @see field
  * @see field_types
  * @see field_formatter
+ * @see plugin_api
  */
 
 /**
@@ -157,15 +172,16 @@ function hook_field_widget_WIDGET_TYPE_form_alter(&$element, &$form_state, $cont
  * choose which formatter to use.
  *
  * Formatters are Plugins managed by the
- * Drupal\Core\Field\FormatterPluginManager class. A formatter
- * is implemented by providing a class that implements
- * Drupal\Core\Field\FormatterInterface (in most cases, by
- * subclassing Drupal\Core\Field\FormatterBase), and provides
- * the proper annotation block.
+ * \Drupal\Core\Field\FormatterPluginManager class. A formatter is a plugin
+ * annotated with class \Drupal\Core\Entity\Annotation\FieldFormatter that
+ * implements \Drupal\Core\Field\FormatterInterface (in most cases, by
+ * subclassing \Drupal\Core\Field\FormatterBase). Formatter plugins need to be
+ * in the namespace \Drupal\{your_module}\Plugin\Field\FieldFormatter.
  *
  * @see field
  * @see field_types
  * @see field_widget
+ * @see plugin_api
  */
 
 /**
diff --git a/core/modules/field/field.module b/core/modules/field/field.module
index f423ff9e98fe7bf84b4e9fe0cdd0c33e70eb00e7..4726101c2ccbacded26f281e7dc775dd24c5e3e8 100644
--- a/core/modules/field/field.module
+++ b/core/modules/field/field.module
@@ -54,9 +54,6 @@
  *
  * - @link field_purge Field API bulk data deletion @endlink: Cleans up after
  *   bulk deletion operations such as deletion of field or field_instance.
- *
- * - @link field_language Field language API @endlink: Provides native
- *   multilingual support for the Field API.
  */
 
 /**