diff --git a/core/includes/common.inc b/core/includes/common.inc
index 6976f9d669a627400506ca270657e5e36c8524e4..da655255561f96884d17d0468e99b97268d4b102 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -310,6 +310,7 @@ function drupal_get_feeds() {
  *     not available, the current path.
  *
  * @see current_path()
+ * @ingroup form_api
  */
 function drupal_get_destination() {
   $destination = &drupal_static(__FUNCTION__);
diff --git a/core/lib/Drupal/Core/Form/FormBase.php b/core/lib/Drupal/Core/Form/FormBase.php
index 8848d3f9cd0e426caac0d2704aa9da29feb3c3bc..b9f04c1a83345ee7c1fa820e5eef6066423ed0e1 100644
--- a/core/lib/Drupal/Core/Form/FormBase.php
+++ b/core/lib/Drupal/Core/Form/FormBase.php
@@ -18,6 +18,8 @@
 
 /**
  * Provides a base class for forms.
+ *
+ * @ingroup form_api
  */
 abstract class FormBase implements FormInterface, ContainerInjectionInterface {
   use StringTranslationTrait;
diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index db2900c9bfc29cb4a98fef2ec4b10bb63f0b6100..c150c29dae0adfa8493bd6bd7a0896bc29339789 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -28,6 +28,8 @@
 
 /**
  * Provides form building and processing.
+ *
+ * @ingroup form_api
  */
 class FormBuilder implements FormBuilderInterface, FormValidatorInterface, FormSubmitterInterface {
 
diff --git a/core/lib/Drupal/Core/Form/FormInterface.php b/core/lib/Drupal/Core/Form/FormInterface.php
index fda5aae197ab94d0ec8e82ea940cf05d292d2e41..40daf12c1043f8287add534c106958f5a729cdef 100644
--- a/core/lib/Drupal/Core/Form/FormInterface.php
+++ b/core/lib/Drupal/Core/Form/FormInterface.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides an interface for a Form.
+ *
+ * @ingroup form_api
  */
 interface FormInterface {
 
diff --git a/core/lib/Drupal/Core/Queue/Batch.php b/core/lib/Drupal/Core/Queue/Batch.php
index 56ec94fb154e8984fcdcd04ebbb261dfe50f48e8..750b90fae610caefa574bfa4ef7f36cc4c4c38f1 100644
--- a/core/lib/Drupal/Core/Queue/Batch.php
+++ b/core/lib/Drupal/Core/Queue/Batch.php
@@ -17,6 +17,8 @@
  *
  * Stale items from failed batches are cleaned from the {queue} table on cron
  * using the 'created' date.
+ *
+ * @ingroup queue
  */
 class Batch extends DatabaseQueue {
 
diff --git a/core/lib/Drupal/Core/Queue/BatchMemory.php b/core/lib/Drupal/Core/Queue/BatchMemory.php
index fcc49f5c7a9580eea75fb57b4b0394fe2af09c0a..e17e7adc708c94c578ae44772e23b7ac2c298b12 100644
--- a/core/lib/Drupal/Core/Queue/BatchMemory.php
+++ b/core/lib/Drupal/Core/Queue/BatchMemory.php
@@ -15,6 +15,8 @@
  * - Ensures FIFO ordering.
  * - Allows an item to be repeatedly claimed until it is actually deleted (no
  *   notion of lease time or 'expire' date), to allow multipass operations.
+ *
+ * @ingroup queue
  */
 class BatchMemory extends Memory {
 
diff --git a/core/lib/Drupal/Core/Queue/DatabaseQueue.php b/core/lib/Drupal/Core/Queue/DatabaseQueue.php
index 82d0cb4f734910cb91490f3258811e6d089c425b..d4dd5d6ce7f44bedb5697da36fb615bc315b9bed 100644
--- a/core/lib/Drupal/Core/Queue/DatabaseQueue.php
+++ b/core/lib/Drupal/Core/Queue/DatabaseQueue.php
@@ -11,6 +11,8 @@
 
 /**
  * Default queue implementation.
+ *
+ * @ingroup queue
  */
 class DatabaseQueue implements ReliableQueueInterface {
 
diff --git a/core/lib/Drupal/Core/Queue/Memory.php b/core/lib/Drupal/Core/Queue/Memory.php
index eb25f9a7a3c558549ab061616fb72bc74262183b..0dff021134a65d1845edaca56fdd9a955078243b 100644
--- a/core/lib/Drupal/Core/Queue/Memory.php
+++ b/core/lib/Drupal/Core/Queue/Memory.php
@@ -13,6 +13,8 @@
  * This allows "undelayed" variants of processes relying on the Queue
  * interface. The queue data resides in memory. It should only be used for
  * items that will be queued and dequeued within a given page request.
+ *
+ * @ingroup queue
  */
 class Memory implements QueueInterface {
   /**
diff --git a/core/lib/Drupal/Core/Queue/QueueInterface.php b/core/lib/Drupal/Core/Queue/QueueInterface.php
index 0b7b4cfacfef2177f6c4b95d2777ee6af9ca7d47..d9afc5f0bf0899d016734ade68a6f112ccdcde1d 100644
--- a/core/lib/Drupal/Core/Queue/QueueInterface.php
+++ b/core/lib/Drupal/Core/Queue/QueueInterface.php
@@ -12,6 +12,8 @@
  *
  * Classes implementing this interface will do a best effort to preserve order
  * in messages and to execute them at least once.
+ *
+ * @ingroup queue
  */
 interface QueueInterface {
 
diff --git a/core/lib/Drupal/Core/Queue/ReliableQueueInterface.php b/core/lib/Drupal/Core/Queue/ReliableQueueInterface.php
index 7f7f8b227a711e02922a60ee5e45e50e91975a89..f36c23dc84a5cac669f07e31770d92ae2065b984 100644
--- a/core/lib/Drupal/Core/Queue/ReliableQueueInterface.php
+++ b/core/lib/Drupal/Core/Queue/ReliableQueueInterface.php
@@ -12,6 +12,8 @@
  *
  * Classes implementing this interface preserve the order of messages and
  * guarantee that every item will be executed at least once.
+ *
+ * @ingroup queue
  */
 interface ReliableQueueInterface extends QueueInterface {
 }
diff --git a/core/modules/file/file.module b/core/modules/file/file.module
index 67634cebda246bc9dc385624b2f772becbd833c2..d676bb57349fc5518edecf96b2506ddc6b2fa2d6 100644
--- a/core/modules/file/file.module
+++ b/core/modules/file/file.module
@@ -1813,6 +1813,8 @@ function file_icon_map(FileInterface $file) {
  * @return
  *   A multidimensional array. The keys are field_name, entity_type,
  *   entity_id and the value is an entity referencing this file.
+ *
+ * @ingroup file
  */
 function file_get_file_references(FileInterface $file, FieldDefinitionInterface $field = NULL, $age = EntityStorageInterface::FIELD_LOAD_REVISION, $field_type = 'file') {
   $references = &drupal_static(__FUNCTION__, array());