diff --git a/core/lib/Drupal/Component/Utility/Crypt.php b/core/lib/Drupal/Component/Utility/Crypt.php
index 7121f7658b51c9f62009453d021d5a42dfa69e9d..535297db33f4a76745881aa605a820983d92dd42 100644
--- a/core/lib/Drupal/Component/Utility/Crypt.php
+++ b/core/lib/Drupal/Component/Utility/Crypt.php
@@ -9,6 +9,8 @@
 
 /**
  * Utility class for cryptographically-secure string handling routines.
+ *
+ * @ingroup utility
  */
 class Crypt {
 
diff --git a/core/lib/Drupal/Component/Utility/DiffArray.php b/core/lib/Drupal/Component/Utility/DiffArray.php
index e496723d6b33bebd7b0e95af3fa9d7462c404975..bd1ef5214c7afbf91601087caa19b6e75f2dcc1d 100644
--- a/core/lib/Drupal/Component/Utility/DiffArray.php
+++ b/core/lib/Drupal/Component/Utility/DiffArray.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides helpers to perform diffs on multi dimensional arrays.
+ *
+ * @ingroup utility
  */
 class DiffArray {
 
diff --git a/core/lib/Drupal/Component/Utility/Html.php b/core/lib/Drupal/Component/Utility/Html.php
index bc0a91621433fb10589ff125854248cb2877e254..2b5455fde84980d26d14001ee442461ead6e00a8 100644
--- a/core/lib/Drupal/Component/Utility/Html.php
+++ b/core/lib/Drupal/Component/Utility/Html.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides DOMDocument helpers for parsing and serializing HTML strings.
+ *
+ * @ingroup utility
  */
 class Html {
 
diff --git a/core/lib/Drupal/Component/Utility/Image.php b/core/lib/Drupal/Component/Utility/Image.php
index dd06806b5f1ff9d286335107694e212522431e38..b12a86133229ef1607d114be642b385720fccb63 100644
--- a/core/lib/Drupal/Component/Utility/Image.php
+++ b/core/lib/Drupal/Component/Utility/Image.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides helpers to operate on images.
+ *
+ * @ingroup utility
  */
 class Image {
 
diff --git a/core/lib/Drupal/Component/Utility/Json.php b/core/lib/Drupal/Component/Utility/Json.php
index 88e55aed192d0b1ceb9a8d4eb870b9d56658fafa..8602d9bff7afef6df01838423e2198ce55ef1881 100644
--- a/core/lib/Drupal/Component/Utility/Json.php
+++ b/core/lib/Drupal/Component/Utility/Json.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides helpers for dealing with json.
+ *
+ * @ingroup utility
  */
 class Json {
 
diff --git a/core/lib/Drupal/Component/Utility/NestedArray.php b/core/lib/Drupal/Component/Utility/NestedArray.php
index acfdc2f9e9455dd74b64a160d7686157a440895a..8e00e068a4a43ff5f66ada93ad529bbca301bc71 100644
--- a/core/lib/Drupal/Component/Utility/NestedArray.php
+++ b/core/lib/Drupal/Component/Utility/NestedArray.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides helpers to perform operations on nested arrays and array keys of variable depth.
+ *
+ * @ingroup utility
  */
 class NestedArray {
 
diff --git a/core/lib/Drupal/Component/Utility/Number.php b/core/lib/Drupal/Component/Utility/Number.php
index 38a524b5aa36dab0c7bf3d196a214bbfdc992e00..453ed4aba2050ec3e64caa3af6fa84bb16fd5cb1 100644
--- a/core/lib/Drupal/Component/Utility/Number.php
+++ b/core/lib/Drupal/Component/Utility/Number.php
@@ -8,6 +8,8 @@
 
 /**
  * Provides helper methods for manipulating numbers.
+ *
+ * @ingroup utility
  */
 class Number {
 
diff --git a/core/lib/Drupal/Component/Utility/Random.php b/core/lib/Drupal/Component/Utility/Random.php
index 2712fba4d2007518c9316ca7b5f69b37e4814d40..f3bc4ae61e3a3c6bc1f52115c7080cb9d8965b45 100644
--- a/core/lib/Drupal/Component/Utility/Random.php
+++ b/core/lib/Drupal/Component/Utility/Random.php
@@ -9,6 +9,8 @@
 
 /**
  * Defines a utility class for creating random data.
+ *
+ * @ingroup utility
  */
 class Random {
 
diff --git a/core/lib/Drupal/Component/Utility/Settings.php b/core/lib/Drupal/Component/Utility/Settings.php
index f6f5e915748297e25d5a9a9a9e9c4210dda82128..2b34090c7284178896548f3b7d4f3322ebf24a76 100644
--- a/core/lib/Drupal/Component/Utility/Settings.php
+++ b/core/lib/Drupal/Component/Utility/Settings.php
@@ -9,6 +9,8 @@
 
 /**
  * Read only settings that are initialized with the class.
+ *
+ * @ingroup utility
  */
 final class Settings {
 
diff --git a/core/lib/Drupal/Component/Utility/SortArray.php b/core/lib/Drupal/Component/Utility/SortArray.php
index 64ceb89862eb6043701c84fa4f5a15f2d52426a9..4774f88e8e247d186a27b95e5b0b86fcb7c3ed1a 100644
--- a/core/lib/Drupal/Component/Utility/SortArray.php
+++ b/core/lib/Drupal/Component/Utility/SortArray.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides generic array sorting helper methods.
+ *
+ * @ingroup utility
  */
 class SortArray {
 
diff --git a/core/lib/Drupal/Component/Utility/String.php b/core/lib/Drupal/Component/Utility/String.php
index affd4df05a133750d799e4839040ec20d4a14a00..cd546ce0a1a401f75a89e0005b1623754b2579dd 100644
--- a/core/lib/Drupal/Component/Utility/String.php
+++ b/core/lib/Drupal/Component/Utility/String.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides helpers to operate on strings.
+ *
+ * @ingroup utility
  */
 class String {
 
diff --git a/core/lib/Drupal/Component/Utility/Tags.php b/core/lib/Drupal/Component/Utility/Tags.php
index db9fca05a5e5750f623af7db798a1b2e6c065f5a..628ce70e9b2354b7074ac16b3b5cba0f2768b46d 100644
--- a/core/lib/Drupal/Component/Utility/Tags.php
+++ b/core/lib/Drupal/Component/Utility/Tags.php
@@ -9,6 +9,8 @@
 
 /**
  * Defines a class that can explode and implode tags.
+ *
+ * @ingroup utility
  */
 class Tags {
 
diff --git a/core/lib/Drupal/Component/Utility/Timer.php b/core/lib/Drupal/Component/Utility/Timer.php
index 294632c4fbc8a1d0917059023d0a45ec04e18f96..714ca03bee969909c3b08f6d0ad4544f001644fd 100644
--- a/core/lib/Drupal/Component/Utility/Timer.php
+++ b/core/lib/Drupal/Component/Utility/Timer.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides helpers to use timers throughout a request.
+ *
+ * @ingroup utility
  */
 class Timer {
 
diff --git a/core/lib/Drupal/Component/Utility/Unicode.php b/core/lib/Drupal/Component/Utility/Unicode.php
index c5e0d82e9ac029d7efe86f93b24eb144afcbd280..01e6a1f83c14c0662de7c3fcf4d793432271d3fb 100644
--- a/core/lib/Drupal/Component/Utility/Unicode.php
+++ b/core/lib/Drupal/Component/Utility/Unicode.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides Unicode-related conversions and operations.
+ *
+ * @ingroup utility
  */
 class Unicode {
 
diff --git a/core/lib/Drupal/Component/Utility/UrlHelper.php b/core/lib/Drupal/Component/Utility/UrlHelper.php
index bf956c9940f12454988bf5eb87b5a6839edcf68e..a216f2140f9b46227ed7d408da42cd5d57080bf6 100644
--- a/core/lib/Drupal/Component/Utility/UrlHelper.php
+++ b/core/lib/Drupal/Component/Utility/UrlHelper.php
@@ -9,6 +9,8 @@
 
 /**
  * Helper class URL based methods.
+ *
+ * @ingroup utility
  */
 class UrlHelper {
 
diff --git a/core/lib/Drupal/Component/Utility/UserAgent.php b/core/lib/Drupal/Component/Utility/UserAgent.php
index 361b057ce9f19970a44af597861419ba9f82903b..d91074b18bedf30e9d5d51f871b049757520d6b7 100644
--- a/core/lib/Drupal/Component/Utility/UserAgent.php
+++ b/core/lib/Drupal/Component/Utility/UserAgent.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides user agent related utility functions.
+ *
+ * @ingroup utility
  */
 class UserAgent {
 
diff --git a/core/lib/Drupal/Component/Utility/Variable.php b/core/lib/Drupal/Component/Utility/Variable.php
index 81378960e61bbc0e6e843af6ef1cf31fdb2b6da9..2da908b3f2fafcaeea8d65f9b4321ab9763ca298 100644
--- a/core/lib/Drupal/Component/Utility/Variable.php
+++ b/core/lib/Drupal/Component/Utility/Variable.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides helpers for dealing with variables.
+ *
+ * @ingroup utility
  */
 class Variable {
 
diff --git a/core/lib/Drupal/Component/Utility/Xss.php b/core/lib/Drupal/Component/Utility/Xss.php
index df96015010b046e86d2c1026043772ce2cec37f1..dc499136abb9551a32c179816a7e4192e52d0917 100644
--- a/core/lib/Drupal/Component/Utility/Xss.php
+++ b/core/lib/Drupal/Component/Utility/Xss.php
@@ -9,6 +9,8 @@
 
 /**
  * Provides helper to filter for cross-site scripting.
+ *
+ * @ingroup utility
  */
 class Xss {
 
diff --git a/core/modules/system/core.api.php b/core/modules/system/core.api.php
index 379954955539e741a8aa7cc50c0d45d7599350c1..04289c47da7190403d179ade0299a95d88340290 100644
--- a/core/modules/system/core.api.php
+++ b/core/modules/system/core.api.php
@@ -38,10 +38,11 @@
  * - @link views_overview Views @endlink
  * - @link database Database abstraction layer @endlink
  *
- * @section utility Other essential APIs
+ * @section other_essentials Other essential APIs
  *
  * - @link i18n Internationalization @endlink
  * - @link cache Caching @endlink
+ * - @link utility Utility classes and functions @endlink
  * - @link user_api User accounts, permissions, and roles @endlink
  * - @link theme_render Theme system and render API @endlink
  * - @link migration Migration @endlink
@@ -476,3 +477,25 @@
  * - Automated testing: @link testing Automated tests topic @endlink
  * @}
  */
+
+/**
+ * @defgroup utility Utility classes and functions
+ * @{
+ * Overview of utility classes and functions for developers.
+ *
+ * Drupal provides developers with a variety of utility functions that make it
+ * easier and more efficient to perform tasks that are either really common,
+ * tedious, or difficult. Utility functions help to reduce code duplication and
+ * should be used in place of one-off code whenever possible.
+ *
+ * @see common.inc
+ * @see file
+ * @see format
+ * @see mail.inc
+ * @see php_wrappers
+ * @see sanitization
+ * @see session.inc
+ * @see transliteration
+ * @see validation
+ * @}
+ */