diff --git a/core/lib/Drupal/Core/Field/Entity/BaseFieldOverride.php b/core/lib/Drupal/Core/Field/Entity/BaseFieldOverride.php
index 973105dea630dda3279645a379199f72935aa76d..0f28e265203bef6d9cb2796916332e2662135f9e 100644
--- a/core/lib/Drupal/Core/Field/Entity/BaseFieldOverride.php
+++ b/core/lib/Drupal/Core/Field/Entity/BaseFieldOverride.php
@@ -177,6 +177,7 @@ public function getUniqueIdentifier() {
    * Gets the base field definition.
    *
    * @return \Drupal\Core\Field\BaseFieldDefinition
+   *   An associative array of the base field definition.
    */
   protected function getBaseFieldDefinition() {
     if (!isset($this->baseFieldDefinition)) {
diff --git a/core/lib/Drupal/Core/Field/FieldDefinitionInterface.php b/core/lib/Drupal/Core/Field/FieldDefinitionInterface.php
index 369f07e1503cd049e6e334af42aeb8086c0ad0e9..b24279ab00f27159f208d18b5fa9c927f80fb99b 100644
--- a/core/lib/Drupal/Core/Field/FieldDefinitionInterface.php
+++ b/core/lib/Drupal/Core/Field/FieldDefinitionInterface.php
@@ -258,6 +258,7 @@ public function getFieldStorageDefinition();
    *   The bundle to get the configurable field for.
    *
    * @return \Drupal\Core\Field\FieldConfigInterface
+   *   The configuration entity for the field.
    */
   public function getConfig($bundle);
 
@@ -265,6 +266,7 @@ public function getConfig($bundle);
    * Returns a unique identifier for the field.
    *
    * @return string
+   *   The unique ID for the field.
    */
   public function getUniqueIdentifier();
 
diff --git a/core/lib/Drupal/Core/Field/FieldStorageDefinitionEvent.php b/core/lib/Drupal/Core/Field/FieldStorageDefinitionEvent.php
index ce3f17897209424ecac2de4587f6f528d887e7ec..fdb1db0d21ebcc160ac5c7016d8d294b97266a7a 100644
--- a/core/lib/Drupal/Core/Field/FieldStorageDefinitionEvent.php
+++ b/core/lib/Drupal/Core/Field/FieldStorageDefinitionEvent.php
@@ -41,6 +41,7 @@ public function __construct(FieldStorageDefinitionInterface $field_storage_defin
    * The field storage definition.
    *
    * @return \Drupal\Core\Field\FieldStorageDefinitionInterface
+   *   The field storage definition for the entity.
    */
   public function getFieldStorageDefinition() {
     return $this->fieldStorageDefinition;
@@ -50,6 +51,7 @@ public function getFieldStorageDefinition() {
    * The original field storage definition.
    *
    * @return \Drupal\Core\Field\FieldStorageDefinitionInterface
+   *   The field storage definition for the original entity.
    */
   public function getOriginal() {
     return $this->original;
diff --git a/core/lib/Drupal/Core/Field/FieldStorageDefinitionInterface.php b/core/lib/Drupal/Core/Field/FieldStorageDefinitionInterface.php
index ead716800865c4d101c951eee233a00fca827d6a..36b7e4eaf3842c3699c3517360efa7c47af6eed9 100644
--- a/core/lib/Drupal/Core/Field/FieldStorageDefinitionInterface.php
+++ b/core/lib/Drupal/Core/Field/FieldStorageDefinitionInterface.php
@@ -326,6 +326,7 @@ public function isBaseField();
    * Returns a unique identifier for the field storage.
    *
    * @return string
+   *   A unique identifier for the field storage.
    */
   public function getUniqueStorageIdentifier();
 
diff --git a/core/lib/Drupal/Core/Form/FormBase.php b/core/lib/Drupal/Core/Form/FormBase.php
index 6e6e5e5327b8fc07e4cb809a54ea2ce26522ff12..3688de7c35cc64cba6d79e7eeb2056f2c838ab83 100644
--- a/core/lib/Drupal/Core/Form/FormBase.php
+++ b/core/lib/Drupal/Core/Form/FormBase.php
@@ -116,6 +116,7 @@ protected function config($name) {
    * when the config factory needs to be manipulated directly.
    *
    * @return \Drupal\Core\Config\ConfigFactoryInterface
+   *   The configuration factory for this form.
    */
   protected function configFactory() {
     if (!$this->configFactory) {
@@ -161,6 +162,7 @@ protected function getRequest() {
    * Gets the route match.
    *
    * @return \Drupal\Core\Routing\RouteMatchInterface
+   *   The currently active route match object.
    */
   protected function getRouteMatch() {
     if (!$this->routeMatch) {
diff --git a/core/lib/Drupal/Core/Form/FormBuilderInterface.php b/core/lib/Drupal/Core/Form/FormBuilderInterface.php
index 66d9da4c2f1e7a6b5ed896e8c097a24469b5fca5..0f785819d3599d536ea157084f126cc0892ae3f0 100644
--- a/core/lib/Drupal/Core/Form/FormBuilderInterface.php
+++ b/core/lib/Drupal/Core/Form/FormBuilderInterface.php
@@ -185,6 +185,7 @@ public function submitForm($form_arg, FormStateInterface &$form_state, mixed ...
    *   array.
    *
    * @return mixed|\Symfony\Component\HttpFoundation\Response
+   *   The form array or a response object.
    */
   public function retrieveForm($form_id, FormStateInterface &$form_state);
 
@@ -205,6 +206,7 @@ public function retrieveForm($form_id, FormStateInterface &$form_state);
    *   sanitized \Drupal::request()->request data, is also accumulated here.
    *
    * @return \Symfony\Component\HttpFoundation\RedirectResponse|null
+   *   The form response or NULL when the form was submitted programmatically.
    */
   public function processForm($form_id, &$form, FormStateInterface &$form_state);
 
@@ -318,6 +320,7 @@ public function prepareForm($form_id, &$form, FormStateInterface &$form_state);
    *   as well as the sanitized \Drupal::request()->request data.
    *
    * @return array
+   *   The completely built form.
    */
   public function doBuildForm($form_id, &$element, FormStateInterface &$form_state);
 
diff --git a/core/lib/Drupal/Core/Form/FormState.php b/core/lib/Drupal/Core/Form/FormState.php
index edb8ec781cacae48fb30ad251ca1d4677e230892..a83fcc323e0a18908302edecb3fb7d22757f661a 100644
--- a/core/lib/Drupal/Core/Form/FormState.php
+++ b/core/lib/Drupal/Core/Form/FormState.php
@@ -660,6 +660,8 @@ public function setRequestMethod($method) {
    * have side-effects, such as persisting $form_state changes.
    *
    * @return bool
+   *   TRUE if the request method is considered a safe HTTP method. Otherwise
+   *   FALSE.
    *
    * @see \Symfony\Component\HttpFoundation\Request::isMethodSafe()
    * @see https://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.1
diff --git a/core/lib/Drupal/Core/Form/FormStateInterface.php b/core/lib/Drupal/Core/Form/FormStateInterface.php
index d517666cf29bfc88a7c10b92181dfd8095112c48..f4a9e114e38310f7466df616e2fb96efdab6f469 100644
--- a/core/lib/Drupal/Core/Form/FormStateInterface.php
+++ b/core/lib/Drupal/Core/Form/FormStateInterface.php
@@ -748,6 +748,7 @@ public function setGroups(array $groups);
    * Returns references to details elements to render them within vertical tabs.
    *
    * @return array
+   *   References to details elements to render them within vertical tabs.
    */
   public function &getGroups();
 
@@ -924,6 +925,7 @@ public function setProgrammedBypassAccessCheck($programmed_bypass_access_check =
    * Determines if this form submission should bypass #access.
    *
    * @return bool
+   *   TRUE if this form bypassing access checked, otherwise FALSE.
    *
    * @see \Drupal\Core\Form\FormState::$programmed_bypass_access_check
    */
diff --git a/core/lib/Drupal/Core/Form/FormSubmitterInterface.php b/core/lib/Drupal/Core/Form/FormSubmitterInterface.php
index 9d078b3ca332e85cf0000b23b16065383abc74e7..0d9ac2d62e8a89f9fbc8f86d12d49e7a1fd61ab0 100644
--- a/core/lib/Drupal/Core/Form/FormSubmitterInterface.php
+++ b/core/lib/Drupal/Core/Form/FormSubmitterInterface.php
@@ -69,6 +69,8 @@ public function executeSubmitHandlers(&$form, FormStateInterface &$form_state);
    *   The current state of the form.
    *
    * @return \Symfony\Component\HttpFoundation\RedirectResponse|null
+   *   The HTTP response if the form submission results in a redirect, otherwise
+   *   NULL.
    *
    * @see \Drupal\Core\Form\FormBuilderInterface::processForm()
    * @see \Drupal\Core\Form\FormBuilderInterface::buildForm()
diff --git a/core/lib/Drupal/Core/Form/FormValidator.php b/core/lib/Drupal/Core/Form/FormValidator.php
index def5f87191d3cff658337683e7c0cbb2d9950171..862bf9703d3b99cb03e3ac41b61fbecf830b8f3c 100644
--- a/core/lib/Drupal/Core/Form/FormValidator.php
+++ b/core/lib/Drupal/Core/Form/FormValidator.php
@@ -386,6 +386,8 @@ protected function performRequiredValidation(&$elements, FormStateInterface &$fo
    *   The current state of the form.
    *
    * @return array|null
+   *   An array of validation errors for the triggering element. Defaults to
+   *   NULL, which turns off error suppression.
    */
   protected function determineLimitValidationErrors(FormStateInterface &$form_state) {
     // While this element is being validated, it may be desired that some
diff --git a/core/lib/Drupal/Core/Form/SubformState.php b/core/lib/Drupal/Core/Form/SubformState.php
index bec19be6205177ecd8ddbc85dacdbda823c5d0c1..ffe4a1d8c0342fea7aac30195a5ca3b3c0ee89e2 100644
--- a/core/lib/Drupal/Core/Form/SubformState.php
+++ b/core/lib/Drupal/Core/Form/SubformState.php
@@ -68,6 +68,7 @@ public static function createForSubform(array &$subform, array &$parent_form, Fo
    *   The property name (#parents or #array_parents).
    *
    * @return mixed
+   *   The form parents relative to its parent form.
    *
    * @throws \InvalidArgumentException
    *   Thrown when the requested property does not exist.
diff --git a/core/lib/Drupal/Core/Form/SubformStateInterface.php b/core/lib/Drupal/Core/Form/SubformStateInterface.php
index 99bef57d256a9671266a7ee21efe28f0b13784e8..10e213be39c89b468e9288052c17b69276dc2011 100644
--- a/core/lib/Drupal/Core/Form/SubformStateInterface.php
+++ b/core/lib/Drupal/Core/Form/SubformStateInterface.php
@@ -45,6 +45,7 @@ interface SubformStateInterface extends FormStateInterface {
    * Gets the complete form state.
    *
    * @return \Drupal\Core\Form\FormStateInterface
+   *   The form state.
    */
   public function getCompleteFormState();
 
diff --git a/core/lib/Drupal/Core/GeneratedLink.php b/core/lib/Drupal/Core/GeneratedLink.php
index 7bebcbaf31d800d775485fb2d1d7a98bedd4f084..19414e2a807d394a51fb66b2d77cc91120178352 100644
--- a/core/lib/Drupal/Core/GeneratedLink.php
+++ b/core/lib/Drupal/Core/GeneratedLink.php
@@ -30,6 +30,7 @@ class GeneratedLink extends BubbleableMetadata implements MarkupInterface, \Coun
    * Gets the generated link.
    *
    * @return string
+   *   The generated link.
    */
   public function getGeneratedLink() {
     return $this->generatedLink;
diff --git a/core/lib/Drupal/Core/GeneratedUrl.php b/core/lib/Drupal/Core/GeneratedUrl.php
index 47d0f350a4a8abade2628ff986854d9964e65014..caa6ae9346eaecdbc9e947c8ec400f14481b64d9 100644
--- a/core/lib/Drupal/Core/GeneratedUrl.php
+++ b/core/lib/Drupal/Core/GeneratedUrl.php
@@ -23,6 +23,7 @@ class GeneratedUrl extends BubbleableMetadata {
    * Gets the generated URL.
    *
    * @return string
+   *   The generated URL.
    */
   public function getGeneratedUrl() {
     return $this->generatedUrl;
diff --git a/core/lib/Drupal/Core/Hook/HookCollectorPass.php b/core/lib/Drupal/Core/Hook/HookCollectorPass.php
index 5d99ac7720980cfcfe0e4c85555660971c2e821a..abebad92b175878d6ca3ceabcc6f284c932e28fc 100644
--- a/core/lib/Drupal/Core/Hook/HookCollectorPass.php
+++ b/core/lib/Drupal/Core/Hook/HookCollectorPass.php
@@ -164,8 +164,6 @@ public static function collectAllHookImplementations(array $module_filenames, ?C
    *   matched first.
    * @param $skip_procedural
    *   Skip the procedural check for the current module.
-   *
-   * @return void
    */
   protected function collectModuleHookImplementations($dir, $module, $module_preg, bool $skip_procedural): void {
     $hook_file_cache = FileCacheFactory::get('hook_implementations');
@@ -304,10 +302,8 @@ protected static function getHookAttributesInClass(string $class): array {
    *   The class in which said attribute resides in.
    * @param $module
    *   The module in which the class resides in.
-   *
-   * @return void
    */
-  protected function addFromAttribute(Hook $hook, $class, $module) {
+  protected function addFromAttribute(Hook $hook, $class, $module): void {
     if ($hook->module) {
       $module = $hook->module;
     }
@@ -326,10 +322,8 @@ protected function addFromAttribute(Hook $hook, $class, $module) {
    *   The name of the module. (Truly shocking!)
    * @param string $function
    *   The name of function implementing the hook. (Wow!)
-   *
-   * @return void
    */
-  protected function addProceduralImplementation(\SplFileInfo $fileinfo, string $hook, string $module, string $function) {
+  protected function addProceduralImplementation(\SplFileInfo $fileinfo, string $hook, string $module, string $function): void {
     $this->addFromAttribute(new Hook($hook, $module . '_' . $hook), ProceduralCall::class, $module);
     if ($hook === 'hook_info') {
       $this->hookInfo[] = $function;
@@ -369,8 +363,6 @@ public function getImplementations(): array {
    *   The hook to check.
    * @param string $class
    *   The class the hook is implemented on.
-   *
-   * @return void
    */
   public static function checkForProceduralOnlyHooks(Hook $hook, string $class): void {
     $staticDenyHooks = [
diff --git a/core/lib/Drupal/Core/Http/LinkRelationTypeInterface.php b/core/lib/Drupal/Core/Http/LinkRelationTypeInterface.php
index 7faaa0443092bdcb26ce065fc077f8d08a42881b..d9ff775f6c43de177bd62dbbfc8a86bbed2a3499 100644
--- a/core/lib/Drupal/Core/Http/LinkRelationTypeInterface.php
+++ b/core/lib/Drupal/Core/Http/LinkRelationTypeInterface.php
@@ -17,6 +17,7 @@ interface LinkRelationTypeInterface {
    * Indicates whether this link relation type is of the 'registered' kind.
    *
    * @return bool
+   *   TRUE if the link relation is registered, FALSE otherwise.
    *
    * @see https://tools.ietf.org/html/rfc5988#section-4.1
    */
@@ -26,6 +27,7 @@ public function isRegistered();
    * Indicates whether this link relation type is of the 'extension' kind.
    *
    * @return bool
+   *   TRUE if the link relation is an extension type, FALSE otherwise.
    *
    * @see https://tools.ietf.org/html/rfc5988#section-4.2
    */
diff --git a/core/lib/Drupal/Core/ImageToolkit/ImageToolkitOperationBase.php b/core/lib/Drupal/Core/ImageToolkit/ImageToolkitOperationBase.php
index d7a6f70c54aaf2c203cdf2d8f0fb9a9cf87041d4..0cca18d6fd486b0797e061643da60fcb0556af4b 100644
--- a/core/lib/Drupal/Core/ImageToolkit/ImageToolkitOperationBase.php
+++ b/core/lib/Drupal/Core/ImageToolkit/ImageToolkitOperationBase.php
@@ -59,6 +59,7 @@ public function __construct(array $configuration, $plugin_id, array $plugin_defi
    * image toolkit operation developers.
    *
    * @return \Drupal\Core\ImageToolkit\ImageToolkitInterface
+   *   The image toolkit in use.
    */
   protected function getToolkit() {
     return $this->toolkit;
diff --git a/core/lib/Drupal/Core/Installer/Exception/InstallerException.php b/core/lib/Drupal/Core/Installer/Exception/InstallerException.php
index d0e0b6be7ff9b1ae5ff49df3932c152fac63f97a..beb0e9dc535f30102396d47274b2fcdb9140b6c8 100644
--- a/core/lib/Drupal/Core/Installer/Exception/InstallerException.php
+++ b/core/lib/Drupal/Core/Installer/Exception/InstallerException.php
@@ -38,6 +38,7 @@ public function __construct($message, $title = 'Error', $code = 0, ?\Exception $
    * Returns the exception page title.
    *
    * @return string
+   *   The page title.
    */
   public function getTitle() {
     return $this->title;
diff --git a/core/lib/Drupal/Core/Installer/InstallerRedirectTrait.php b/core/lib/Drupal/Core/Installer/InstallerRedirectTrait.php
index f6acafb6a8f266c5aea0a0e18d680c7c6d3d1cfe..e68e33016d9afde309140436ed6818a0d8ae9fb2 100644
--- a/core/lib/Drupal/Core/Installer/InstallerRedirectTrait.php
+++ b/core/lib/Drupal/Core/Installer/InstallerRedirectTrait.php
@@ -18,6 +18,7 @@ trait InstallerRedirectTrait {
    * Returns whether the current PHP process runs on CLI.
    *
    * @return bool
+   *   TRUE if the current PHP process is running on CLI, otherwise FALSE.
    */
   protected function isCli() {
     return PHP_SAPI === 'cli';
diff --git a/core/lib/Drupal/Core/Layout/LayoutDefault.php b/core/lib/Drupal/Core/Layout/LayoutDefault.php
index bd3780987a4dd18a7c646f92c1545fd2d4b069e5..0c9b4063ad7444ee64a1daacb6e13abfc5ee90f0 100644
--- a/core/lib/Drupal/Core/Layout/LayoutDefault.php
+++ b/core/lib/Drupal/Core/Layout/LayoutDefault.php
@@ -96,6 +96,7 @@ public function calculateDependencies() {
    *
    * @return \Drupal\Core\Layout\LayoutDefinition
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getPluginDefinition() {
     return parent::getPluginDefinition();
   }
diff --git a/core/lib/Drupal/Core/Layout/LayoutInterface.php b/core/lib/Drupal/Core/Layout/LayoutInterface.php
index 33858a546d7fc0f2696c408873f4b9bf51cb9b7c..b3b61a9f74f2b29f2df97a3999fc0ef14e191f53 100644
--- a/core/lib/Drupal/Core/Layout/LayoutInterface.php
+++ b/core/lib/Drupal/Core/Layout/LayoutInterface.php
@@ -30,6 +30,7 @@ public function build(array $regions);
    *
    * @return \Drupal\Core\Layout\LayoutDefinition
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getPluginDefinition();
 
 }
diff --git a/core/lib/Drupal/Core/Layout/LayoutPluginManager.php b/core/lib/Drupal/Core/Layout/LayoutPluginManager.php
index 76140b3af04a380b127c67b9efa3f1caef9304f0..b0fad27e11e9de6a09c4531422aeb4d140d888c8 100644
--- a/core/lib/Drupal/Core/Layout/LayoutPluginManager.php
+++ b/core/lib/Drupal/Core/Layout/LayoutPluginManager.php
@@ -197,6 +197,7 @@ public function getCategories() {
    *
    * @return \Drupal\Core\Layout\LayoutDefinition[]
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getSortedDefinitions(?array $definitions = NULL, $label_key = 'label') {
     // Sort the plugins first by category, then by label.
     $definitions = $definitions ?? $this->getDefinitions();
@@ -214,6 +215,7 @@ public function getSortedDefinitions(?array $definitions = NULL, $label_key = 'l
    *
    * @return \Drupal\Core\Layout\LayoutDefinition[][]
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getGroupedDefinitions(?array $definitions = NULL, $label_key = 'label') {
     $definitions = $this->getSortedDefinitions($definitions ?? $this->getDefinitions(), $label_key);
     $grouped_definitions = [];
diff --git a/core/lib/Drupal/Core/Layout/LayoutPluginManagerInterface.php b/core/lib/Drupal/Core/Layout/LayoutPluginManagerInterface.php
index 366b1d41f65c3ec17e7d8e245a2519d4c3d753a3..a2b877335a957953a259a8617f507a58463be6c4 100644
--- a/core/lib/Drupal/Core/Layout/LayoutPluginManagerInterface.php
+++ b/core/lib/Drupal/Core/Layout/LayoutPluginManagerInterface.php
@@ -25,6 +25,7 @@ public function getThemeImplementations();
    *
    * @return \Drupal\Core\Layout\LayoutInterface
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function createInstance($plugin_id, array $configuration = []);
 
   /**
@@ -32,6 +33,7 @@ public function createInstance($plugin_id, array $configuration = []);
    *
    * @return \Drupal\Core\Layout\LayoutDefinition|null
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getDefinition($plugin_id, $exception_on_invalid = TRUE);
 
   /**
@@ -39,6 +41,7 @@ public function getDefinition($plugin_id, $exception_on_invalid = TRUE);
    *
    * @return \Drupal\Core\Layout\LayoutDefinition[]
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getDefinitions();
 
   /**
@@ -46,6 +49,7 @@ public function getDefinitions();
    *
    * @return \Drupal\Core\Layout\LayoutDefinition[]
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getSortedDefinitions(?array $definitions = NULL);
 
   /**
@@ -53,6 +57,7 @@ public function getSortedDefinitions(?array $definitions = NULL);
    *
    * @return \Drupal\Core\Layout\LayoutDefinition[][]
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getGroupedDefinitions(?array $definitions = NULL);
 
   /**
diff --git a/core/lib/Drupal/Core/Link.php b/core/lib/Drupal/Core/Link.php
index 28f6ed98f7f55f759b24081590cd760296da27c1..2b97938d5ecfedca0b5771068fe121b03ee19b7b 100644
--- a/core/lib/Drupal/Core/Link.php
+++ b/core/lib/Drupal/Core/Link.php
@@ -129,6 +129,7 @@ public function setText($text) {
    * Returns the URL of the link.
    *
    * @return \Drupal\Core\Url
+   *   The URL object.
    */
   public function getUrl() {
     return $this->url;
diff --git a/core/lib/Drupal/Core/Lock/LockBackendInterface.php b/core/lib/Drupal/Core/Lock/LockBackendInterface.php
index aa8707478695576ebccd23463e627a1f5543f4f0..f102126ba9f271ef1bcd2043401c829cb141ebf2 100644
--- a/core/lib/Drupal/Core/Lock/LockBackendInterface.php
+++ b/core/lib/Drupal/Core/Lock/LockBackendInterface.php
@@ -91,6 +91,7 @@ interface LockBackendInterface {
    *   (optional) Lock lifetime in seconds. Defaults to 30.0.
    *
    * @return bool
+   *   TRUE if the lock was successfully acquired, FALSE otherwise.
    */
   public function acquire($name, $timeout = 30.0);
 
@@ -101,6 +102,7 @@ public function acquire($name, $timeout = 30.0);
    *   Lock to acquire.
    *
    * @return bool
+   *   TRUE if the lock can be acquired, FALSE otherwise.
    */
   public function lockMayBeAvailable($name);
 
@@ -146,6 +148,7 @@ public function releaseAll($lockId = NULL);
    * Locks will be wiped out at the end of each page request on a token basis.
    *
    * @return string
+   *   The lock ID.
    */
   public function getLockId();
 
diff --git a/core/lib/Drupal/Core/Menu/LocalActionInterface.php b/core/lib/Drupal/Core/Menu/LocalActionInterface.php
index 81ff308ae8999eca348a1e09a1a1b9870fc135de..83c0f9748f99a9a46f2ac5a17ec01e3d4561a7e1 100644
--- a/core/lib/Drupal/Core/Menu/LocalActionInterface.php
+++ b/core/lib/Drupal/Core/Menu/LocalActionInterface.php
@@ -32,6 +32,7 @@ public function getRouteParameters(RouteMatchInterface $route_match);
    * Returns the weight for the local action.
    *
    * @return int
+   *   The weight of this action.
    */
   public function getWeight();
 
diff --git a/core/lib/Drupal/Core/Menu/MenuLinkManager.php b/core/lib/Drupal/Core/Menu/MenuLinkManager.php
index c89dadd7b0191c1d829def43748afcfa5bd3551c..3e019f5069b608a15e8a0845f971658c38f9f7cc 100644
--- a/core/lib/Drupal/Core/Menu/MenuLinkManager.php
+++ b/core/lib/Drupal/Core/Menu/MenuLinkManager.php
@@ -94,6 +94,7 @@ protected function processDefinition(array &$definition, $plugin_id) {
    * Gets the plugin discovery.
    *
    * @return \Drupal\Component\Plugin\Discovery\DiscoveryInterface
+   *   The discovery service.
    */
   protected function getDiscovery() {
     if (!isset($this->discovery)) {
@@ -109,6 +110,7 @@ protected function getDiscovery() {
    * Gets the plugin factory.
    *
    * @return \Drupal\Component\Plugin\Factory\FactoryInterface
+   *   The plugin factory.
    */
   protected function getFactory() {
     if (!isset($this->factory)) {
diff --git a/core/lib/Drupal/Core/Plugin/Context/ContextAwarePluginManagerTrait.php b/core/lib/Drupal/Core/Plugin/Context/ContextAwarePluginManagerTrait.php
index afe2aa59e12382cf0613fbf236b59478ca1fd3a6..cddeeb0e88da3baac0ec2f42d8549c37b30aabec 100644
--- a/core/lib/Drupal/Core/Plugin/Context/ContextAwarePluginManagerTrait.php
+++ b/core/lib/Drupal/Core/Plugin/Context/ContextAwarePluginManagerTrait.php
@@ -11,6 +11,7 @@ trait ContextAwarePluginManagerTrait {
    * Wraps the context handler.
    *
    * @return \Drupal\Core\Plugin\Context\ContextHandlerInterface
+   *   The context handler service.
    */
   protected function contextHandler() {
     return \Drupal::service('context.handler');
diff --git a/core/lib/Drupal/Core/Plugin/Context/ContextInterface.php b/core/lib/Drupal/Core/Plugin/Context/ContextInterface.php
index 260cb2c33d25d8938adb507493b72eaaf0303c69..89ebd9e5ebeaf5f83454a66acfa936a9e38020e0 100644
--- a/core/lib/Drupal/Core/Plugin/Context/ContextInterface.php
+++ b/core/lib/Drupal/Core/Plugin/Context/ContextInterface.php
@@ -18,12 +18,14 @@ interface ContextInterface extends ComponentContextInterface, CacheableDependenc
    *
    * @return \Drupal\Core\Plugin\Context\ContextDefinitionInterface
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getContextDefinition();
 
   /**
    * Gets the context value as typed data object.
    *
    * @return \Drupal\Core\TypedData\TypedDataInterface
+   *   The typed data object associated with the context.
    */
   public function getContextData();
 
diff --git a/core/lib/Drupal/Core/Plugin/ContextAwarePluginAssignmentTrait.php b/core/lib/Drupal/Core/Plugin/ContextAwarePluginAssignmentTrait.php
index 75cbc681f82e21926454277ab75d4deb4c8ebebc..035c69809a319ce4af1a75d3f24bfc4caae05ab9 100644
--- a/core/lib/Drupal/Core/Plugin/ContextAwarePluginAssignmentTrait.php
+++ b/core/lib/Drupal/Core/Plugin/ContextAwarePluginAssignmentTrait.php
@@ -18,6 +18,7 @@ abstract protected function t($string, array $args = [], array $options = []);
    * Wraps the context handler.
    *
    * @return \Drupal\Core\Plugin\Context\ContextHandlerInterface
+   *   the context handler service.
    */
   protected function contextHandler() {
     return \Drupal::service('context.handler');
diff --git a/core/lib/Drupal/Core/Plugin/ContextAwarePluginTrait.php b/core/lib/Drupal/Core/Plugin/ContextAwarePluginTrait.php
index 133c9caf48f73b34fc9d7e116875df6f871929aa..42a9e1acc4b47363eb5f648a2cffaec7aec167fe 100644
--- a/core/lib/Drupal/Core/Plugin/ContextAwarePluginTrait.php
+++ b/core/lib/Drupal/Core/Plugin/ContextAwarePluginTrait.php
@@ -123,6 +123,7 @@ abstract public function getPluginDefinition();
    *
    * @return \Drupal\Core\Plugin\Context\ContextDefinitionInterface[]
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getContextDefinitions() {
     $definition = $this->getPluginDefinition();
     if ($definition instanceof ContextAwarePluginDefinitionInterface) {
@@ -137,6 +138,7 @@ public function getContextDefinitions() {
    *
    * @return \Drupal\Core\Plugin\Context\ContextDefinitionInterface
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getContextDefinition($name) {
     $definition = $this->getPluginDefinition();
     if ($definition instanceof ContextAwarePluginDefinitionInterface) {
diff --git a/core/lib/Drupal/Core/Queue/QueueWorkerManager.php b/core/lib/Drupal/Core/Queue/QueueWorkerManager.php
index 23496592cc925e8703f42743c56287f864ed859c..7bb1797ae5690aa99d21b05a4faaba948dc9e202 100644
--- a/core/lib/Drupal/Core/Queue/QueueWorkerManager.php
+++ b/core/lib/Drupal/Core/Queue/QueueWorkerManager.php
@@ -58,6 +58,7 @@ public function processDefinition(&$definition, $plugin_id) {
    * {@inheritdoc}
    *
    * @return \Drupal\Core\Queue\QueueWorkerInterface
+   *   A fully configured plugin instance.
    */
   public function createInstance($plugin_id, array $configuration = []) {
     return parent::createInstance($plugin_id, $configuration);
diff --git a/core/lib/Drupal/Core/Render/Element/HtmlTag.php b/core/lib/Drupal/Core/Render/Element/HtmlTag.php
index 0d69b2f0706ff5bdc6ec2eb3be0aee31d05573e6..cde78beb48c6480776890ada6f88ab5a1887797e 100644
--- a/core/lib/Drupal/Core/Render/Element/HtmlTag.php
+++ b/core/lib/Drupal/Core/Render/Element/HtmlTag.php
@@ -80,6 +80,7 @@ public function getInfo() {
    *     any non-empty value here will add the <noscript> tag.)
    *
    * @return array
+   *   The element, after the pre-rendering processing run.
    */
   public static function preRenderHtmlTag($element) {
     $attributes = isset($element['#attributes']) ? new Attribute($element['#attributes']) : '';
diff --git a/core/lib/Drupal/Core/Render/Element/InlineTemplate.php b/core/lib/Drupal/Core/Render/Element/InlineTemplate.php
index d9a60d9af79bf77c858650d421f8a5213ad430b4..9ff9ace07061c07b91c5a5909b3d12ca3e701dd8 100644
--- a/core/lib/Drupal/Core/Render/Element/InlineTemplate.php
+++ b/core/lib/Drupal/Core/Render/Element/InlineTemplate.php
@@ -48,6 +48,7 @@ public function getInfo() {
    *
    * @return array
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public static function preRenderInlineTemplate($element) {
     /** @var \Drupal\Core\Template\TwigEnvironment $environment */
     $environment = \Drupal::service('twig');
diff --git a/core/lib/Drupal/Core/Render/Element/Pager.php b/core/lib/Drupal/Core/Render/Element/Pager.php
index 1977b5bf6d39bbf3cf89cf6cc6720e82cbf95038..1f23a11ebcea463f3c3d55a2ae19c012e516b677 100644
--- a/core/lib/Drupal/Core/Render/Element/Pager.php
+++ b/core/lib/Drupal/Core/Render/Element/Pager.php
@@ -68,6 +68,7 @@ public function getInfo() {
    *   A renderable array of #type => pager.
    *
    * @return array
+   *   The render array with cache contexts added.
    */
   public static function preRenderPager(array $pager) {
     // Note: the default pager theme process function
diff --git a/core/lib/Drupal/Core/Render/Element/StatusReport.php b/core/lib/Drupal/Core/Render/Element/StatusReport.php
index fe55e9652bb297ac99128cd82f1f93d82f98684d..579a8c853ee817373027368c0804d994ab45986a 100644
--- a/core/lib/Drupal/Core/Render/Element/StatusReport.php
+++ b/core/lib/Drupal/Core/Render/Element/StatusReport.php
@@ -65,6 +65,8 @@ public static function preRenderGroupRequirements($element) {
    * Gets the severities.
    *
    * @return array
+   *   An associative array of the requirements severities. The keys are the
+   *   requirement constants defined in install.inc.
    */
   public static function getSeverities() {
     return [
diff --git a/core/lib/Drupal/Core/Render/Element/Table.php b/core/lib/Drupal/Core/Render/Element/Table.php
index 9026d05914f863b9c55ddb35cbe640c58bbdbc32..53767dc7cdd71b48a69cb50372dab6aff0271927 100644
--- a/core/lib/Drupal/Core/Render/Element/Table.php
+++ b/core/lib/Drupal/Core/Render/Element/Table.php
@@ -383,6 +383,7 @@ public static function validateTable(&$element, FormStateInterface $form_state,
    *     $options array.
    *
    * @return array
+   *   Associative array of rendered child elements for a table.
    *
    * @see template_preprocess_table()
    * @see \Drupal\Core\Render\AttachmentsResponseProcessorInterface::processAttachments()
diff --git a/core/lib/Drupal/Core/Render/ElementInfoManager.php b/core/lib/Drupal/Core/Render/ElementInfoManager.php
index e01630258d9ab8f85799c0afdb7a16dce5ac8c02..07a7880743af84849ea3ef15f13ac2f9f080d397 100644
--- a/core/lib/Drupal/Core/Render/ElementInfoManager.php
+++ b/core/lib/Drupal/Core/Render/ElementInfoManager.php
@@ -86,6 +86,7 @@ public function getInfoProperty($type, $property_name, $default = NULL) {
    *   The theme name.
    *
    * @return array
+   *   An array containing all element information.
    */
   protected function buildInfo($theme_name) {
     // Get cached definitions.
@@ -137,6 +138,7 @@ protected function buildInfo($theme_name) {
    *
    * @return \Drupal\Core\Render\Element\ElementInterface
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function createInstance($plugin_id, array $configuration = []) {
     return parent::createInstance($plugin_id, $configuration);
   }
@@ -164,6 +166,7 @@ public function clearCachedDefinitions() {
    *   The theme name.
    *
    * @return string
+   *   The cache ID.
    */
   protected function getCid($theme_name) {
     return 'element_info_build:' . $theme_name;
diff --git a/core/lib/Drupal/Core/Render/PageDisplayVariantSelectionEvent.php b/core/lib/Drupal/Core/Render/PageDisplayVariantSelectionEvent.php
index b95ff18b550f7f5a84cab6beba9852dcfffeb13f..afe9f8bfe2b5c0405e8f15ecaf0a90e69e7c2271 100644
--- a/core/lib/Drupal/Core/Render/PageDisplayVariantSelectionEvent.php
+++ b/core/lib/Drupal/Core/Render/PageDisplayVariantSelectionEvent.php
@@ -81,6 +81,7 @@ public function setPluginId($plugin_id) {
    * The selected page display variant plugin ID.
    *
    * @return string
+   *   The plugin ID.
    */
   public function getPluginId() {
     return $this->pluginId;
@@ -103,6 +104,7 @@ public function setPluginConfiguration(array $configuration) {
    * Get the configuration for the selected page display variant.
    *
    * @return array
+   *   The plugin configuration.
    */
   public function getPluginConfiguration() {
     return $this->pluginConfiguration;
diff --git a/core/lib/Drupal/Core/Render/PlaceholderGeneratorInterface.php b/core/lib/Drupal/Core/Render/PlaceholderGeneratorInterface.php
index 1e13e5eb7836d1ce660335a27a2d45ce4edfb0f2..1a83553a719c55457f380367a5749ebcf3d59314 100644
--- a/core/lib/Drupal/Core/Render/PlaceholderGeneratorInterface.php
+++ b/core/lib/Drupal/Core/Render/PlaceholderGeneratorInterface.php
@@ -24,6 +24,8 @@ interface PlaceholderGeneratorInterface {
    *   analyzed.
    *
    * @return bool
+   *   Returns TRUE is the render array can be overwritten with placeholders,
+   *   FALSE otherwise.
    */
   public function canCreatePlaceholder(array $element);
 
diff --git a/core/lib/Drupal/Core/Routing/Enhancer/EntityRevisionRouteEnhancer.php b/core/lib/Drupal/Core/Routing/Enhancer/EntityRevisionRouteEnhancer.php
index 71107c685d77d5f001db42def57109e277704324..fb5a5d369cffad3ec478e3b78e8baf7d279321be 100644
--- a/core/lib/Drupal/Core/Routing/Enhancer/EntityRevisionRouteEnhancer.php
+++ b/core/lib/Drupal/Core/Routing/Enhancer/EntityRevisionRouteEnhancer.php
@@ -19,6 +19,7 @@ class EntityRevisionRouteEnhancer implements EnhancerInterface {
    *   The current route.
    *
    * @return bool
+   *   TRUE if the enhancer runs on the current route, FALSE otherwise.
    */
   protected function applies(Route $route) {
     // Check whether there is any entity revision parameter.
diff --git a/core/lib/Drupal/Core/Routing/Enhancer/FormRouteEnhancer.php b/core/lib/Drupal/Core/Routing/Enhancer/FormRouteEnhancer.php
index 6ddb85cb9ec98445bbb4815b01c5e33e718f54f6..998b1319fd7c39e2d5dcf5a2f932d26c65565719 100644
--- a/core/lib/Drupal/Core/Routing/Enhancer/FormRouteEnhancer.php
+++ b/core/lib/Drupal/Core/Routing/Enhancer/FormRouteEnhancer.php
@@ -19,6 +19,7 @@ class FormRouteEnhancer implements EnhancerInterface {
    *   The current route.
    *
    * @return bool
+   *   TRUE when the enhancer runs on the current route, FALSE otherwise.
    */
   protected function applies(Route $route) {
     return $route->hasDefault('_form') && !$route->hasDefault('_controller');
diff --git a/core/lib/Drupal/Core/Routing/RedirectDestinationInterface.php b/core/lib/Drupal/Core/Routing/RedirectDestinationInterface.php
index 46e8566d20d8da0e7c72fc58b67d41441ef26d8c..1efd0f2c0ebdc4773ea497b6cf281ba3d823ff0f 100644
--- a/core/lib/Drupal/Core/Routing/RedirectDestinationInterface.php
+++ b/core/lib/Drupal/Core/Routing/RedirectDestinationInterface.php
@@ -38,6 +38,7 @@ public function getAsArray();
    * @endcode
    *
    * @return string
+   *   The full path of the destination.
    */
   public function get();
 
diff --git a/core/lib/Drupal/Core/Routing/RouteProvider.php b/core/lib/Drupal/Core/Routing/RouteProvider.php
index 132f89631b0809fcfa36f44507878786a50a3d75..eba5bca5bf313b1a0acdfdc23af947f394a1a9fa 100644
--- a/core/lib/Drupal/Core/Routing/RouteProvider.php
+++ b/core/lib/Drupal/Core/Routing/RouteProvider.php
@@ -481,6 +481,7 @@ protected function getRouteCollectionCacheId(Request $request) {
    *   Request.
    *
    * @return string
+   *   The query parameters identifier for the route collection cache.
    */
   protected function getQueryParametersCacheIdPart(Request $request) {
     // @todo Use \Symfony\Component\HttpFoundation\Request::normalizeQueryString
diff --git a/core/lib/Drupal/Core/Routing/StackedRouteMatchInterface.php b/core/lib/Drupal/Core/Routing/StackedRouteMatchInterface.php
index c20796fe86e6bb4333ee2f8e77636ab077babc87..ea615a8fa4e43f90f21bc95bea639d547a519f6b 100644
--- a/core/lib/Drupal/Core/Routing/StackedRouteMatchInterface.php
+++ b/core/lib/Drupal/Core/Routing/StackedRouteMatchInterface.php
@@ -15,6 +15,7 @@ interface StackedRouteMatchInterface extends RouteMatchInterface {
    * Gets the current route match.
    *
    * @return \Drupal\Core\Routing\RouteMatchInterface
+   *   The route match object for the current route.
    */
   public function getCurrentRouteMatch();
 
@@ -22,6 +23,7 @@ public function getCurrentRouteMatch();
    * Gets the master route match..
    *
    * @return \Drupal\Core\Routing\RouteMatchInterface
+   *   The route match object for the master route.
    */
   public function getMasterRouteMatch();
 
diff --git a/core/lib/Drupal/Core/Session/RefinableCalculatedPermissionsInterface.php b/core/lib/Drupal/Core/Session/RefinableCalculatedPermissionsInterface.php
index 5965d91ce8dcc06ac304e5756e2dc356d3df3eae..db8334e99a43229d3929917f2f7b12a0015e569b 100644
--- a/core/lib/Drupal/Core/Session/RefinableCalculatedPermissionsInterface.php
+++ b/core/lib/Drupal/Core/Session/RefinableCalculatedPermissionsInterface.php
@@ -19,7 +19,7 @@ interface RefinableCalculatedPermissionsInterface extends RefinableCacheableDepe
    *   given identifier within the scope. Defaults to FALSE, meaning a merge
    *   will take place instead.
    *
-   * @return self
+   * @return $this
    */
   public function addItem(CalculatedPermissionsItemInterface $item, bool $overwrite = FALSE): self;
 
@@ -32,7 +32,7 @@ public function addItem(CalculatedPermissionsItemInterface $item, bool $overwrit
    *   (optional) The scope identifier to remove the item from, defaults to
    *   'drupal'.
    *
-   * @return self
+   * @return $this
    */
   public function removeItem(string $scope = AccessPolicyInterface::SCOPE_DRUPAL, string|int $identifier = AccessPolicyInterface::SCOPE_DRUPAL): self;
 
@@ -49,7 +49,7 @@ public function removeItems(): self;
    * @param string $scope
    *   The scope name to remove the items for.
    *
-   * @return self
+   * @return $this
    */
   public function removeItemsByScope(string $scope): self;
 
@@ -61,7 +61,7 @@ public function removeItemsByScope(string $scope): self;
    * @param \Drupal\Core\Session\CalculatedPermissionsInterface $other
    *   The other calculated permissions object to merge into this one.
    *
-   * @return self
+   * @return $this
    */
   public function merge(CalculatedPermissionsInterface $other): self;
 
diff --git a/core/lib/Drupal/Core/Session/SessionManager.php b/core/lib/Drupal/Core/Session/SessionManager.php
index 1004b1f6621f5e5a67a577ee5f13ce999a67ddff..0170626181c06b0295a8667edd2b67850a27da3a 100644
--- a/core/lib/Drupal/Core/Session/SessionManager.php
+++ b/core/lib/Drupal/Core/Session/SessionManager.php
@@ -249,6 +249,7 @@ public function setWriteSafeHandler(WriteSafeSessionHandlerInterface $handler) {
    * Command line clients do not support cookies nor sessions.
    *
    * @return bool
+   *   TRUE if the current PHP process runs on CLI, otherwise FALSE>
    */
   protected function isCli() {
     return PHP_SAPI === 'cli';
diff --git a/core/lib/Drupal/Core/Site/Settings.php b/core/lib/Drupal/Core/Site/Settings.php
index 16b70a0c95f3680ec76ff22a7af8ef9e4554dff8..63b56a865d495c2a7633b2d0d3a3a9af34d9206c 100644
--- a/core/lib/Drupal/Core/Site/Settings.php
+++ b/core/lib/Drupal/Core/Site/Settings.php
@@ -61,7 +61,7 @@ public function __construct(array $settings) {
    * A singleton is used because this class is used before the container is
    * available.
    *
-   * @return \Drupal\Core\Site\Settings
+   * @return $this
    *
    * @throws \BadMethodCallException
    *   Thrown when the settings instance has not been initialized yet.
diff --git a/core/lib/Drupal/Core/StackMiddleware/AjaxPageState.php b/core/lib/Drupal/Core/StackMiddleware/AjaxPageState.php
index 060d9253208065df1a86de53e91c7ab1b5304142..0deb986c3c9f63bcf33ef55e9c2e89bbfab28c1f 100644
--- a/core/lib/Drupal/Core/StackMiddleware/AjaxPageState.php
+++ b/core/lib/Drupal/Core/StackMiddleware/AjaxPageState.php
@@ -45,6 +45,8 @@ public function handle(Request $request, $type = self::MAIN_REQUEST, $catch = TR
    *   An array of query parameters, where the libraries parameter is compressed.
    *
    * @return array
+   *   The input array of query parameters, where the libraries parameter is
+   *   changed to be uncompressed.
    */
   private function parseAjaxPageState(array $ajax_page_state): array {
     $ajax_page_state['libraries'] = UrlHelper::uncompressQueryParameter($ajax_page_state['libraries']);
diff --git a/core/lib/Drupal/Core/StreamWrapper/StreamWrapperInterface.php b/core/lib/Drupal/Core/StreamWrapper/StreamWrapperInterface.php
index ef4245f45485e574bfc277e2ca4874c895402b2d..f9de7760aab42e892d9b86b4165a81a1c7e4a95b 100644
--- a/core/lib/Drupal/Core/StreamWrapper/StreamWrapperInterface.php
+++ b/core/lib/Drupal/Core/StreamWrapper/StreamWrapperInterface.php
@@ -100,6 +100,8 @@ interface StreamWrapperInterface extends PhpStreamWrapperInterface {
    * Returns the type of stream wrapper.
    *
    * @return int
+   *   The type of stream wrapper. This should be one of the constants in this
+   *   class.
    */
   public static function getType();
 
diff --git a/core/lib/Drupal/Core/StringTranslation/PluralTranslatableMarkup.php b/core/lib/Drupal/Core/StringTranslation/PluralTranslatableMarkup.php
index 4255e893368a319d545d17a079793b7a52774104..49a2e0bfaad288686d14a55cb50cdbe910b81f60 100644
--- a/core/lib/Drupal/Core/StringTranslation/PluralTranslatableMarkup.php
+++ b/core/lib/Drupal/Core/StringTranslation/PluralTranslatableMarkup.php
@@ -123,6 +123,9 @@ public function render() {
    * Gets the plural index through the gettext formula.
    *
    * @return int
+   *   The numeric index of the plural variant to use for this language and
+   *   count combination. Defaults to -1 when the language was not found or does
+   *   not have a plural formula.
    */
   protected function getPluralIndex() {
     // We have to test both if the function and the service exist since in
diff --git a/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php b/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
index 336de03794ec860daf9bebcfaa8d8c92673fb5de..744953dc574f12bd2b3d41a4bd42f2b1c5f35844 100644
--- a/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
+++ b/core/lib/Drupal/Core/Template/TwigPhpStorageCache.php
@@ -62,6 +62,7 @@ public function __construct(CacheBackendInterface $cache, $twig_cache_prefix) {
    * Gets the PHP code storage object to use for the compiled Twig files.
    *
    * @return \Drupal\Component\PhpStorage\PhpStorageInterface
+   *   The PhpStorage object used for storing the templates.
    */
   protected function storage() {
     if (!isset($this->storage)) {
diff --git a/core/lib/Drupal/Core/Theme/ActiveTheme.php b/core/lib/Drupal/Core/Theme/ActiveTheme.php
index 08eaf9108a79b42c570c1439487727dbc070c6bf..f417a10a74917aa6e6ae584bd6e140ab3734bfaa 100644
--- a/core/lib/Drupal/Core/Theme/ActiveTheme.php
+++ b/core/lib/Drupal/Core/Theme/ActiveTheme.php
@@ -127,6 +127,7 @@ public function __construct(array $values) {
    * Returns the machine name of the theme.
    *
    * @return string
+   *   The machine name for the theme.
    */
   public function getName() {
     return $this->name;
@@ -136,6 +137,7 @@ public function getName() {
    * Returns the path to the theme directory.
    *
    * @return string
+   *   The file path of the theme directory.
    */
   public function getPath() {
     return $this->path;
@@ -145,6 +147,7 @@ public function getPath() {
    * Returns the theme engine.
    *
    * @return string
+   *   The engine of the theme.
    */
   public function getEngine() {
     return $this->engine;
@@ -153,9 +156,10 @@ public function getEngine() {
   /**
    * Returns the path to the theme engine for root themes.
    *
-   * @see \Drupal\Core\Extension\ThemeExtensionList::doList()
-   *
    * @return mixed
+   *   The path to the theme engine for root themes.
+   *
+   * @see \Drupal\Core\Extension\ThemeExtensionList::doList()
    */
   public function getOwner() {
     return $this->owner;
@@ -165,6 +169,7 @@ public function getOwner() {
    * Returns the extension object.
    *
    * @return \Drupal\Core\Extension\Extension
+   *   The extension object for the theme.
    */
   public function getExtension() {
     return $this->extension;
@@ -174,6 +179,7 @@ public function getExtension() {
    * Returns the libraries provided by the theme.
    *
    * @return mixed
+   *   The libraries provided by the theme.
    */
   public function getLibraries() {
     return $this->libraries;
@@ -187,6 +193,7 @@ public function getLibraries() {
    * be called first, so this order needs to be reversed with array_reverse()
    *
    * @return \Drupal\Core\Extension\Extension[]
+   *   An array of base theme extension objects keyed by name.
    */
   public function getBaseThemeExtensions() {
     return $this->baseThemeExtensions;
diff --git a/core/lib/Drupal/Core/Theme/Registry.php b/core/lib/Drupal/Core/Theme/Registry.php
index 66f4225c945bc3f73bdc99c733621cd7b356b53b..1c9c04b8a9c749452301aabc7fd2ff0ecd5e38f4 100644
--- a/core/lib/Drupal/Core/Theme/Registry.php
+++ b/core/lib/Drupal/Core/Theme/Registry.php
@@ -287,6 +287,10 @@ public function get() {
    * Gets the theme registry cache.
    *
    * @return array|null
+   *   The complete theme registry data array for the active theme for this
+   *   registry.
+   *
+   * @see Registry::$registry
    */
   protected function cacheGet(): ?array {
     $theme_name = $this->theme->getName();
diff --git a/core/lib/Drupal/Core/Theme/ThemeInitialization.php b/core/lib/Drupal/Core/Theme/ThemeInitialization.php
index 8f4ef074f57dd0690aa1fbae4c31b85775a20de0..10f173a15e70796bebc494f2e9c26e1f4b3deb05 100644
--- a/core/lib/Drupal/Core/Theme/ThemeInitialization.php
+++ b/core/lib/Drupal/Core/Theme/ThemeInitialization.php
@@ -262,6 +262,7 @@ public function getActiveTheme(Extension $theme, array $base_themes = []) {
    * Gets all extensions.
    *
    * @return array
+   *   An associative array whose keys are the names of the extensions.
    */
   protected function getExtensions() {
     if (!isset($this->extensions)) {
diff --git a/core/lib/Drupal/Core/Theme/ThemeManagerInterface.php b/core/lib/Drupal/Core/Theme/ThemeManagerInterface.php
index 71dc3b56bdfe28c8198379107717e0d2e5d02419..e93d4d25382c5ff793dee96730d5bb1aef06825e 100644
--- a/core/lib/Drupal/Core/Theme/ThemeManagerInterface.php
+++ b/core/lib/Drupal/Core/Theme/ThemeManagerInterface.php
@@ -36,6 +36,7 @@ public function render($hook, array $variables);
    *   The route match.
    *
    * @return \Drupal\Core\Theme\ActiveTheme
+   *   The active theme object.
    */
   public function getActiveTheme(?RouteMatchInterface $route_match = NULL);
 
@@ -43,6 +44,7 @@ public function getActiveTheme(?RouteMatchInterface $route_match = NULL);
    * Determines whether there is an active theme.
    *
    * @return bool
+   *   TRUE if there is an active theme, FALSE otherwise.
    */
   public function hasActiveTheme();
 
diff --git a/core/lib/Drupal/Core/TypedData/DataDefinition.php b/core/lib/Drupal/Core/TypedData/DataDefinition.php
index 48058e33cebae693d13738a1e347bc6736c199d6..66145088839ecd7eb46c4acf0e9f9c5ab70958d6 100644
--- a/core/lib/Drupal/Core/TypedData/DataDefinition.php
+++ b/core/lib/Drupal/Core/TypedData/DataDefinition.php
@@ -361,6 +361,7 @@ public function offsetUnset($offset): void {
    * Returns all definition values as array.
    *
    * @return array
+   *   The array holding values for all definition keys.
    */
   public function toArray() {
     return $this->definition;
diff --git a/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php
index 52b9c47307f079805a5950540f3aa236bda2c7d1..12a4f211e130a32b850830ee2e7f3f64ce485ddd 100644
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/ItemList.php
@@ -217,6 +217,7 @@ public function appendItem($value = NULL) {
    * Helper for creating a list item object.
    *
    * @return \Drupal\Core\TypedData\TypedDataInterface
+   *   The new property instance.
    */
   protected function createItem($offset = 0, $value = NULL) {
     return $this->getTypedDataManager()->getPropertyInstance($this, $offset, $value);
diff --git a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Language.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Language.php
index f81358d5b5bcbeabb5e00106badb33c274586cdf..40d74a8853a6cf3c2ba6f03c673f089a76166ad1 100644
--- a/core/lib/Drupal/Core/TypedData/Plugin/DataType/Language.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Language.php
@@ -33,10 +33,11 @@ class Language extends TypedData {
   protected $language;
 
   /**
-   * Overrides TypedData::getValue().
+   * {@inheritdoc}
    *
    * @return \Drupal\Core\Language\LanguageInterface|null
    */
+  // phpcs:ignore Drupal.Commenting.FunctionComment.MissingReturnComment
   public function getValue() {
     if (!isset($this->language) && $this->id) {
       $this->language = \Drupal::languageManager()->getLanguage($this->id);
diff --git a/core/lib/Drupal/Core/TypedData/PrimitiveInterface.php b/core/lib/Drupal/Core/TypedData/PrimitiveInterface.php
index 1df50f78dc4447afdb2a9b90839a81f6b2ed1847..bf36d72cc229f3d0ab8dcac9b77c335c3bf8bea3 100644
--- a/core/lib/Drupal/Core/TypedData/PrimitiveInterface.php
+++ b/core/lib/Drupal/Core/TypedData/PrimitiveInterface.php
@@ -13,6 +13,7 @@ interface PrimitiveInterface {
    * Gets the primitive data value.
    *
    * @return mixed
+   *   The primitive data value.
    */
   public function getValue();
 
@@ -29,6 +30,7 @@ public function setValue($value);
    * Gets the primitive data value casted to the correct PHP type.
    *
    * @return mixed
+   *   The primitive data value cast to the correct PHP type.
    */
   public function getCastedValue();
 
diff --git a/core/lib/Drupal/Core/Update/UpdateRegistry.php b/core/lib/Drupal/Core/Update/UpdateRegistry.php
index 07e57dd031a1ba05ce1a6c243da16df6d75917f8..d315143cb2c1da82b00da143a9691126872a2707 100644
--- a/core/lib/Drupal/Core/Update/UpdateRegistry.php
+++ b/core/lib/Drupal/Core/Update/UpdateRegistry.php
@@ -287,6 +287,7 @@ public function filterOutInvokedUpdatesByExtension(string $extension) {
 
   /**
    * @return bool
+   *   TRUE if themes are to be updated, FALSE otherwise.
    */
   protected function includeThemes(): bool {
     return $this->updateType === 'post_update';
diff --git a/core/lib/Drupal/Core/Updater/Module.php b/core/lib/Drupal/Core/Updater/Module.php
index 6c2d58f3a4995ce7c7cf3e9f4d3ec52ddfe1d7bf..3cb0c88cd146045fa5958554d22bd4ae66a91f0c 100644
--- a/core/lib/Drupal/Core/Updater/Module.php
+++ b/core/lib/Drupal/Core/Updater/Module.php
@@ -69,6 +69,7 @@ public static function canUpdateDirectory($directory) {
    *   The project to check.
    *
    * @return bool
+   *   TRUE if the the project can be updated, FALSE otherwise.
    */
   public static function canUpdate($project_name) {
     return (bool) \Drupal::service('extension.list.module')->getPath($project_name);
diff --git a/core/lib/Drupal/Core/Updater/Theme.php b/core/lib/Drupal/Core/Updater/Theme.php
index 32da14d8feba308563ca5edcb356e88ad9f35723..2954d5a5085ddf4a7a810db75151750551d5336f 100644
--- a/core/lib/Drupal/Core/Updater/Theme.php
+++ b/core/lib/Drupal/Core/Updater/Theme.php
@@ -70,6 +70,7 @@ public static function canUpdateDirectory($directory) {
    *   The project to check.
    *
    * @return bool
+   *   TRUE if the the project can be updated, FALSE otherwise.
    */
   public static function canUpdate($project_name) {
     return (bool) \Drupal::service('extension.list.theme')->getPath($project_name);
diff --git a/core/lib/Drupal/Core/Updater/UpdaterInterface.php b/core/lib/Drupal/Core/Updater/UpdaterInterface.php
index e925dd443306d70971372888c3dccb13adfbb25d..1ebfd31f0f0e101802b9220f967835c733b99b92 100644
--- a/core/lib/Drupal/Core/Updater/UpdaterInterface.php
+++ b/core/lib/Drupal/Core/Updater/UpdaterInterface.php
@@ -18,6 +18,7 @@ interface UpdaterInterface {
    * Checks if the project is installed.
    *
    * @return bool
+   *   Return TRUE if the project is installed, FALSE otherwise.
    */
   public function isInstalled();
 
diff --git a/core/lib/Drupal/Core/Url.php b/core/lib/Drupal/Core/Url.php
index d16ef550651737852d6d794ddd3f83864f943f4d..8f0de5f32244e69c0462b94e7e6ddd2aaada4846 100644
--- a/core/lib/Drupal/Core/Url.php
+++ b/core/lib/Drupal/Core/Url.php
@@ -544,6 +544,7 @@ public function toUriString() {
    * Indicates if this URL is external.
    *
    * @return bool
+   *   TRUE if the URL is external, FALSE otherwise.
    */
   public function isExternal() {
     return $this->external;
@@ -553,6 +554,7 @@ public function isExternal() {
    * Indicates if this URL has a Drupal route.
    *
    * @return bool
+   *   TRUE if there is a Drupal route for the URL, FALSE otherwise.
    */
   public function isRouted() {
     return !$this->unrouted;
@@ -562,6 +564,7 @@ public function isRouted() {
    * Returns the route name.
    *
    * @return string
+   *   The name of the route.
    *
    * @throws \UnexpectedValueException
    *   If this is a URI with no corresponding route.
@@ -578,6 +581,7 @@ public function getRouteName() {
    * Returns the route parameters.
    *
    * @return array
+   *   An associative array of route parameters.
    *
    * @throws \UnexpectedValueException
    *   If this is a URI with no corresponding route.
@@ -817,6 +821,7 @@ public function access(?AccountInterface $account = NULL, $return_as_object = FA
 
   /**
    * @return \Drupal\Core\Access\AccessManagerInterface
+   *   The access manager service.
    */
   protected function accessManager() {
     if (!isset($this->accessManager)) {
diff --git a/core/phpcs.xml.dist b/core/phpcs.xml.dist
index f63fe23ffa55a368f62c919d8460b6a555367f8a..1144bf1f37d00527b443288f6ecdf4622c0b425b 100644
--- a/core/phpcs.xml.dist
+++ b/core/phpcs.xml.dist
@@ -81,7 +81,7 @@
     <include-pattern>core/lib/Component/*</include-pattern>
   </rule>
   <rule ref="Drupal.Commenting.FunctionComment.MissingReturnComment">
-    <include-pattern>core/lib/Drupal/Core/[a-e]*/*</include-pattern>
+    <include-pattern>core/lib/Drupal/Core/*</include-pattern>
   </rule>
   <rule ref="Drupal.Commenting.GenderNeutralComment"/>
   <rule ref="Drupal.Commenting.HookComment"/>