diff --git a/controller/argument_value_resolver.rst b/controller/argument_value_resolver.rst
index da209a731df..90763c591c0 100644
--- a/controller/argument_value_resolver.rst
+++ b/controller/argument_value_resolver.rst
@@ -76,6 +76,7 @@ In the next example, you'll create a value resolver to inject the object that
 represents the current user whenever a controller method type-hints an argument
 with the ``User`` class::
 
+    // src/Controller/UserController.php
     namespace App\Controller;
 
     use App\Entity\User;
diff --git a/controller/error_pages.rst b/controller/error_pages.rst
index 613a245ef8d..f3c8256e453 100644
--- a/controller/error_pages.rst
+++ b/controller/error_pages.rst
@@ -208,7 +208,7 @@ JSON/XML/CSV/YAML encoders. When your application throws an exception, Symfony
 can output it in one of those formats. If you want to change the output
 contents, create a new Normalizer that supports the ``FlattenException`` input::
 
-    # src/App/Serializer/MyCustomProblemNormalizer.php
+    # src/Serializer/MyCustomProblemNormalizer.php
     namespace App\Serializer;
 
     use Symfony\Component\ErrorHandler\Exception\FlattenException;
diff --git a/controller/service.rst b/controller/service.rst
index 18ee56ee707..ca2f09b5d70 100644
--- a/controller/service.rst
+++ b/controller/service.rst
@@ -26,6 +26,8 @@ a service like: ``App\Controller\HelloController::index``:
     .. code-block:: php-annotations
 
         // src/Controller/HelloController.php
+        namespace App\Controller;
+
         use Symfony\Component\Routing\Annotation\Route;
 
         class HelloController
@@ -87,6 +89,8 @@ which is a common practice when following the `ADR pattern`_
     .. code-block:: php-annotations
 
         // src/Controller/Hello.php
+        namespace App\Controller;
+
         use Symfony\Component\HttpFoundation\Response;
         use Symfony\Component\Routing\Annotation\Route;
 
diff --git a/controller/soap_web_service.rst b/controller/soap_web_service.rst
index 8d1f7ae1f0a..37c72316878 100644
--- a/controller/soap_web_service.rst
+++ b/controller/soap_web_service.rst
@@ -57,6 +57,7 @@ Finally, below is an example of a controller that is capable of handling a SOAP
 request. Because ``index()`` is accessible via ``/soap``, the WSDL document
 can be retrieved via ``/soap?wsdl``::
 
+    // src/Controller/HelloServiceController.php
     namespace App\Controller;
 
     use App\Service\HelloService;
diff --git a/controller/upload_file.rst b/controller/upload_file.rst
index a50368e9f93..dad80ee957d 100644
--- a/controller/upload_file.rst
+++ b/controller/upload_file.rst
@@ -327,6 +327,8 @@ Then, define a service for this class:
 Now you're ready to use this service in the controller::
 
     // src/Controller/ProductController.php
+    namespace App\Controller;
+
     use App\Service\FileUploader;
     use Symfony\Component\HttpFoundation\Request;
 
diff --git a/deployment/fortrabbit.rst b/deployment/fortrabbit.rst
index f13bf4f0ad4..d2aedab9598 100644
--- a/deployment/fortrabbit.rst
+++ b/deployment/fortrabbit.rst
@@ -9,4 +9,4 @@ Deploying to fortrabbit
 For details on deploying to fortrabbit, see their official documentation:
 `Install Symfony`_
 
-.. _`Install Symfony`: https://help.fortrabbit.com/install-symfony-3-uni
+.. _`Install Symfony`: https://help.fortrabbit.com/install-symfony-5-uni
diff --git a/doctrine/associations.rst b/doctrine/associations.rst
index 017f5903391..8bdddab536b 100644
--- a/doctrine/associations.rst
+++ b/doctrine/associations.rst
@@ -548,6 +548,7 @@ What about *removing* a ``Product`` from a ``Category``? The ``make:entity`` com
 also generated a ``removeProduct()`` method::
 
     // src/Entity/Category.php
+    namespace App\Entity;
 
     // ...
     class Category
diff --git a/doctrine/dbal.rst b/doctrine/dbal.rst
index 8487ffdce91..3d451fb4af6 100644
--- a/doctrine/dbal.rst
+++ b/doctrine/dbal.rst
@@ -44,6 +44,9 @@ if you *don't* want to use the Doctrine ORM.
 You can then access the Doctrine DBAL connection by autowiring the ``Connection``
 object::
 
+    // src/Controller/UserController.php
+    namespace App\Controller;
+
     use Doctrine\DBAL\Driver\Connection;
 
     class UserController extends AbstractController
diff --git a/doctrine/events.rst b/doctrine/events.rst
index 9b44b35cba1..1ce0bfa8ac0 100644
--- a/doctrine/events.rst
+++ b/doctrine/events.rst
@@ -56,6 +56,8 @@ define a callback for the ``prePersist`` Doctrine event:
     .. code-block:: php-annotations
 
         // src/Entity/Product.php
+        namespace App\Entity;
+
         use Doctrine\ORM\Mapping as ORM;
 
         // When using annotations, don't forget to add @ORM\HasLifecycleCallbacks()
diff --git a/doctrine/multiple_entity_managers.rst b/doctrine/multiple_entity_managers.rst
index 132dbaac4ba..faffc480877 100644
--- a/doctrine/multiple_entity_managers.rst
+++ b/doctrine/multiple_entity_managers.rst
@@ -230,6 +230,9 @@ When working with multiple entity managers to generate migrations:
 If you *do* omit the entity manager's name when asking for it,
 the default entity manager (i.e. ``default``) is returned::
 
+    // src/Controller/UserController.php
+    namespace App\Controller;
+
     // ...
 
     use Doctrine\ORM\EntityManagerInterface;
@@ -256,6 +259,9 @@ entity manager to persist and fetch its entities.
 
 The same applies to repository calls::
 
+    // src/Controller/UserController.php
+    namespace App\Controller;
+
     use AcmeStoreBundle\Entity\Customer;
     use AcmeStoreBundle\Entity\Product;
     // ...
diff --git a/doctrine/resolve_target_entity.rst b/doctrine/resolve_target_entity.rst
index a60dfe3e604..36038fd9f3c 100644
--- a/doctrine/resolve_target_entity.rst
+++ b/doctrine/resolve_target_entity.rst
@@ -42,8 +42,8 @@ A Customer entity::
     // src/Entity/Customer.php
     namespace App\Entity;
 
-    use Acme\CustomerBundle\Entity\Customer as BaseCustomer;
-    use Acme\InvoiceBundle\Model\InvoiceSubjectInterface;
+    use App\Entity\CustomerInterface as BaseCustomer;
+    use App\Model\InvoiceSubjectInterface;
     use Doctrine\ORM\Mapping as ORM;
 
     /**
@@ -58,10 +58,10 @@ A Customer entity::
 
 An Invoice entity::
 
-    // src/Acme/InvoiceBundle/Entity/Invoice.php
-    namespace Acme\InvoiceBundle\Entity;
+    // src/Entity/Invoice.php
+    namespace App\Entity;
 
-    use Acme\InvoiceBundle\Model\InvoiceSubjectInterface;
+    use App\Model\InvoiceSubjectInterface;
     use Doctrine\ORM\Mapping as ORM;
 
     /**
@@ -73,7 +73,7 @@ An Invoice entity::
     class Invoice
     {
         /**
-         * @ORM\ManyToOne(targetEntity="Acme\InvoiceBundle\Model\InvoiceSubjectInterface")
+         * @ORM\ManyToOne(targetEntity="App\Model\InvoiceSubjectInterface")
          * @var InvoiceSubjectInterface
          */
         protected $subject;
@@ -81,8 +81,8 @@ An Invoice entity::
 
 An InvoiceSubjectInterface::
 
-    // src/Acme/InvoiceBundle/Model/InvoiceSubjectInterface.php
-    namespace Acme\InvoiceBundle\Model;
+    // src/Model/InvoiceSubjectInterface.php
+    namespace App\Model;
 
     /**
      * An interface that the invoice Subject object should implement.
@@ -115,7 +115,7 @@ about the replacement:
             orm:
                 # ...
                 resolve_target_entities:
-                    Acme\InvoiceBundle\Model\InvoiceSubjectInterface: App\Entity\Customer
+                    App\Model\InvoiceSubjectInterface: App\Entity\Customer
 
     .. code-block:: xml
 
@@ -132,7 +132,7 @@ about the replacement:
             <doctrine:config>
                 <doctrine:orm>
                     <!-- ... -->
-                    <doctrine:resolve-target-entity interface="Acme\InvoiceBundle\Model\InvoiceSubjectInterface">App\Entity\Customer</doctrine:resolve-target-entity>
+                    <doctrine:resolve-target-entity interface="App\Model\InvoiceSubjectInterface">App\Entity\Customer</doctrine:resolve-target-entity>
                 </doctrine:orm>
             </doctrine:config>
         </container>
@@ -140,8 +140,8 @@ about the replacement:
     .. code-block:: php
 
         // config/packages/doctrine.php
-        use Acme\InvoiceBundle\Model\InvoiceSubjectInterface;
         use App\Entity\Customer;
+        use App\Model\InvoiceSubjectInterface;
 
         $container->loadFromExtension('doctrine', [
             'orm' => [
diff --git a/form/create_custom_field_type.rst b/form/create_custom_field_type.rst
index b17add4b3d7..58e265fd2ad 100644
--- a/form/create_custom_field_type.rst
+++ b/form/create_custom_field_type.rst
@@ -287,6 +287,8 @@ to define, validate and process their values::
 Now you can configure these options when using the form type::
 
     // src/Form/Type/OrderType.php
+    namespace App\Form\Type;
+
     // ...
 
     class OrderType extends AbstractType
@@ -310,6 +312,8 @@ Now you can configure these options when using the form type::
 The last step is to use these options when building the form::
 
     // src/Form/Type/PostalAddressType.php
+    namespace App\Form\Type;
+
     // ...
 
     class PostalAddressType extends AbstractType
@@ -453,6 +457,8 @@ defined by the form or be completely independent::
 
 
     // src/Form/Type/PostalAddressType.php
+    namespace App\Form\Type;
+
     use Doctrine\ORM\EntityManagerInterface;
     // ...
 
diff --git a/form/create_form_type_extension.rst b/form/create_form_type_extension.rst
index fb1cd2e02b2..59b1c06e9fe 100644
--- a/form/create_form_type_extension.rst
+++ b/form/create_form_type_extension.rst
@@ -251,6 +251,8 @@ may not be applied to it.
 Another option is to return multiple form types in the ``getExtendedTypes()``
 method to extend all of them::
 
+    // src/Form/Extension/DateTimeExtension.php
+    namespace App\Form\Extension;
     // ...
     use Symfony\Component\Form\Extension\Core\Type\DateTimeType;
     use Symfony\Component\Form\Extension\Core\Type\DateType;
diff --git a/form/dynamic_form_modification.rst b/form/dynamic_form_modification.rst
index f2b37cb07c5..69339480248 100644
--- a/form/dynamic_form_modification.rst
+++ b/form/dynamic_form_modification.rst
@@ -255,6 +255,8 @@ Now that you have all the basics in place you can use the features of the
 security helper to fill in the listener logic::
 
     // src/Form/Type/FriendMessageFormType.php
+    namespace App\Form\Type;
+
     use App\Entity\User;
     use Doctrine\ORM\EntityRepository;
     use Symfony\Bridge\Doctrine\Form\Type\EntityType;
diff --git a/form/inherit_data_option.rst b/form/inherit_data_option.rst
index 113e66d6381..3321ab2153a 100644
--- a/form/inherit_data_option.rst
+++ b/form/inherit_data_option.rst
@@ -126,6 +126,8 @@ access the properties of the ``Customer`` instance instead. Convenient, eh?
 Finally, make this work by adding the location form to your two original forms::
 
     // src/Form/Type/CompanyType.php
+    namespace App\Form\Type;
+
     use App\Entity\Company;
     // ...
 
@@ -141,6 +143,8 @@ Finally, make this work by adding the location form to your two original forms::
 .. code-block:: php
 
     // src/Form/Type/CustomerType.php
+    namespace App\Form\Type;
+
     use App\Entity\Customer;
     // ...
 
diff --git a/form/type_guesser.rst b/form/type_guesser.rst
index b842e12a9ad..f990aad4115 100644
--- a/form/type_guesser.rst
+++ b/form/type_guesser.rst
@@ -82,6 +82,7 @@ The ``TypeGuess`` constructor requires three options:
 With this knowledge, you can implement the ``guessType()`` method of the
 ``PHPDocTypeGuesser``::
 
+    // src/Form/TypeGuesser/PHPDocTypeGuesser.php
     namespace App\Form\TypeGuesser;
 
     use Symfony\Component\Form\Extension\Core\Type\CheckboxType;
@@ -221,7 +222,7 @@ and tag it with ``form.type_guesser``:
     :method:`Symfony\\Component\\Form\\FormFactoryBuilder::addTypeGuessers` of
     the ``FormFactoryBuilder`` to register new type guessers::
 
-        use Acme\Form\PHPDocTypeGuesser;
+        use App\Form\TypeGuesser\PHPDocTypeGuesser;
         use Symfony\Component\Form\Forms;
 
         $formFactory = Forms::createFormFactoryBuilder()
diff --git a/form/use_empty_data.rst b/form/use_empty_data.rst
index c186396f8e4..6a567286094 100644
--- a/form/use_empty_data.rst
+++ b/form/use_empty_data.rst
@@ -44,6 +44,7 @@ that takes arguments. Remember, the default ``data_class`` option calls
 that constructor with no arguments::
 
     // src/Form/Type/BlogType.php
+    namespace App\Form\Type;
 
     // ...
     use App\Entity\Blog;
diff --git a/http_cache/esi.rst b/http_cache/esi.rst
index 31b4c354e37..621f604ea95 100644
--- a/http_cache/esi.rst
+++ b/http_cache/esi.rst
@@ -98,7 +98,8 @@ ticker at the bottom of the content. With ESI, you can cache the news ticker
 independently of the rest of the page::
 
     // src/Controller/DefaultController.php
-
+    namespace App\Controller;
+    
     // ...
     class DefaultController extends AbstractController
     {
diff --git a/http_cache/ssi.rst b/http_cache/ssi.rst
index 7397c7b0a5e..94bab702db4 100644
--- a/http_cache/ssi.rst
+++ b/http_cache/ssi.rst
@@ -85,7 +85,8 @@ to cache a static GDPR content block. With SSI, you can add some expiration
 on this block and keep the page private::
 
     // src/Controller/ProfileController.php
-
+    namespace App\Controller;
+    
     // ...
     class ProfileController extends AbstractController
     {
diff --git a/logging/monolog_console.rst b/logging/monolog_console.rst
index 9eb8b28b062..5c0263c5349 100644
--- a/logging/monolog_console.rst
+++ b/logging/monolog_console.rst
@@ -35,6 +35,9 @@ the current log level and the console verbosity.
 
 The example above could then be rewritten as::
 
+    // src/Command/YourCommand.php
+    namespace App\Command;
+
     use Psr\Log\LoggerInterface;
     use Symfony\Component\Console\Command\Command;
     use Symfony\Component\Console\Input\InputInterface;
diff --git a/logging/processors.rst b/logging/processors.rst
index f2b889461ec..9f46326ddaa 100644
--- a/logging/processors.rst
+++ b/logging/processors.rst
@@ -16,6 +16,7 @@ Sometimes it is hard to tell which entries in the log belong to which session
 and/or request. The following example will add a unique token for each request
 using a processor::
 
+    // src/Logger/SessionRequestProcessor.php
     namespace App\Logger;
 
     use Symfony\Component\HttpFoundation\Session\SessionInterface;
diff --git a/messenger/dispatch_after_current_bus.rst b/messenger/dispatch_after_current_bus.rst
index c2b85c2aaad..e382f49eed3 100644
--- a/messenger/dispatch_after_current_bus.rst
+++ b/messenger/dispatch_after_current_bus.rst
@@ -44,6 +44,7 @@ are dispatched by a handler once that handler has fully finished. This can be by
 using the ``DispatchAfterCurrentBusMiddleware`` and adding a
 ``DispatchAfterCurrentBusStamp`` stamp to :ref:`the message Envelope <messenger-envelopes>`::
 
+    // src/Messenger/CommandHandler/RegisterUserHandler.php
     namespace App\Messenger\CommandHandler;
 
     use App\Entity\User;
@@ -85,6 +86,7 @@ using the ``DispatchAfterCurrentBusMiddleware`` and adding a
 
 .. code-block:: php
 
+    // src/Messenger/EventSubscriber/WhenUserRegisteredThenSendWelcomeEmail.php
     namespace App\Messenger\EventSubscriber;
 
     use App\Entity\User;
diff --git a/reference/configuration/kernel.rst b/reference/configuration/kernel.rst
index 5852927e7ad..6b0ac4279ad 100644
--- a/reference/configuration/kernel.rst
+++ b/reference/configuration/kernel.rst
@@ -33,6 +33,8 @@ To change this value, override the ``getCharset()`` method and return another
 charset::
 
     // src/Kernel.php
+    namespace App;
+
     use Symfony\Component\HttpKernel\Kernel as BaseKernel;
     // ...
 
@@ -89,6 +91,8 @@ override the :method:`Symfony\\Component\\HttpKernel\\Kernel::getProjectDir`
 method to return the right project directory::
 
     // src/Kernel.php
+    namespace App;
+
     use Symfony\Component\HttpKernel\Kernel as BaseKernel;
     // ...