diff --git a/config/packages/security.yaml b/config/packages/security.yaml
index 54fbd6b1..c8e61f87 100644
--- a/config/packages/security.yaml
+++ b/config/packages/security.yaml
@@ -40,7 +40,7 @@ security:
             logout:
                 path: logout
                 target: homepage
-                handlers: [App\EventSubscriber\LogoutListener]
+                handlers: [App\EventSubscriber\LogSystem\LogoutLoggerHandler]
 
             remember_me:
                 secret:   '%kernel.secret%'
diff --git a/config/services.yaml b/config/services.yaml
index f5fa21a8..a08ad9c0 100644
--- a/config/services.yaml
+++ b/config/services.yaml
@@ -48,7 +48,7 @@ services:
         resource: '../src/Controller'
         tags: ['controller.service_arguments']
 
-    App\EventSubscriber\MailFromListener:
+    App\EventSubscriber\SetMailFromSubscriber:
         tags: ['kernel.event_subscriber']
         arguments:
             $email: '%sender_email%'
@@ -75,7 +75,7 @@ services:
         tags:
             - { name: "doctrine.orm.entity_listener" }
 
-    App\EventSubscriber\EventLoggerSubscriber:
+    App\EventSubscriber\LogSystem\EventLoggerSubscriber:
         arguments:
             $save_changed_fields: '%env(bool:HISTORY_SAVE_CHANGED_FIELDS)%'
             $save_changed_data: '%env(bool:HISTORY_SAVE_CHANGED_DATA)%'
@@ -83,7 +83,7 @@ services:
         tags:
             - { name: 'doctrine.event_subscriber' }
 
-    App\EventSubscriber\MigrationListener:
+    App\EventSubscriber\LogSystem\LogDBMigrationSubscriber:
         tags:
             - { name: 'doctrine.event_subscriber' }
 
@@ -138,7 +138,7 @@ services:
         arguments:
             $demo_mode: '%demo_mode%'
 
-    App\EventSubscriber\TimezoneListener:
+    App\EventSubscriber\UserSystem\SetUserTimezoneSubscriber:
         arguments:
             $timezone: '%timezone%'
 
diff --git a/src/EventSubscriber/EventLoggerSubscriber.php b/src/EventSubscriber/LogSystem/EventLoggerSubscriber.php
similarity index 92%
rename from src/EventSubscriber/EventLoggerSubscriber.php
rename to src/EventSubscriber/LogSystem/EventLoggerSubscriber.php
index 8a888ecb..9be5ca86 100644
--- a/src/EventSubscriber/EventLoggerSubscriber.php
+++ b/src/EventSubscriber/LogSystem/EventLoggerSubscriber.php
@@ -1,4 +1,22 @@
 <?php
+/**
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ * Copyright (C) 2019 - 2020 Jan Böhmer (https://github.com/jbtronics)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
 
 declare(strict_types=1);
 
@@ -21,7 +39,7 @@ declare(strict_types=1);
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-namespace App\EventSubscriber;
+namespace App\EventSubscriber\LogSystem;
 
 use App\Entity\Attachments\Attachment;
 use App\Entity\Base\AbstractDBElement;
@@ -47,6 +65,10 @@ use Doctrine\Persistence\Event\LifecycleEventArgs;
 use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\Serializer\SerializerInterface;
 
+/**
+ * This event subscriber write to event log when entities are changed, removed, created.
+ * @package App\EventSubscriber\LogSystem
+ */
 class EventLoggerSubscriber implements EventSubscriber
 {
     /** @var array The given fields will not be saved, because they contain sensitive informations */
diff --git a/src/EventSubscriber/MigrationListener.php b/src/EventSubscriber/LogSystem/LogDBMigrationSubscriber.php
similarity index 94%
rename from src/EventSubscriber/MigrationListener.php
rename to src/EventSubscriber/LogSystem/LogDBMigrationSubscriber.php
index 1b50aaba..1e51d518 100644
--- a/src/EventSubscriber/MigrationListener.php
+++ b/src/EventSubscriber/LogSystem/LogDBMigrationSubscriber.php
@@ -40,7 +40,7 @@ declare(strict_types=1);
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-namespace App\EventSubscriber;
+namespace App\EventSubscriber\LogSystem;
 
 use App\Entity\LogSystem\DatabaseUpdatedLogEntry;
 use App\Services\LogSystem\EventLogger;
@@ -48,7 +48,11 @@ use Doctrine\Common\EventSubscriber;
 use Doctrine\Migrations\Event\MigrationsEventArgs;
 use Doctrine\Migrations\Events;
 
-class MigrationListener implements EventSubscriber
+/**
+ * This subscriber logs databaseMigrations to Event log.
+ * @package App\EventSubscriber
+ */
+class LogDBMigrationSubscriber implements EventSubscriber
 {
     protected $old_version = null;
     protected $new_version = null;
diff --git a/src/EventSubscriber/LogoutListener.php b/src/EventSubscriber/LogSystem/LogoutLoggerHandler.php
similarity index 92%
rename from src/EventSubscriber/LogoutListener.php
rename to src/EventSubscriber/LogSystem/LogoutLoggerHandler.php
index 96adcd8f..f6c91451 100644
--- a/src/EventSubscriber/LogoutListener.php
+++ b/src/EventSubscriber/LogSystem/LogoutLoggerHandler.php
@@ -40,7 +40,7 @@ declare(strict_types=1);
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-namespace App\EventSubscriber;
+namespace App\EventSubscriber\LogSystem;
 
 use App\Entity\LogSystem\UserLogoutLogEntry;
 use App\Entity\UserSystem\User;
@@ -50,7 +50,11 @@ use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
 use Symfony\Component\Security\Http\Logout\LogoutHandlerInterface;
 
-class LogoutListener implements LogoutHandlerInterface
+/**
+ * This handler logs to event log, if a user logs out.
+ * @package App\EventSubscriber\LogSystem
+ */
+class LogoutLoggerHandler implements LogoutHandlerInterface
 {
     protected $logger;
     protected $gpdr_compliance;
diff --git a/src/EventSubscriber/SecurityEventLoggerSubscriber.php b/src/EventSubscriber/LogSystem/SecurityEventLoggerSubscriber.php
similarity index 95%
rename from src/EventSubscriber/SecurityEventLoggerSubscriber.php
rename to src/EventSubscriber/LogSystem/SecurityEventLoggerSubscriber.php
index 77f2f3ca..c7252089 100644
--- a/src/EventSubscriber/SecurityEventLoggerSubscriber.php
+++ b/src/EventSubscriber/LogSystem/SecurityEventLoggerSubscriber.php
@@ -18,7 +18,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-namespace App\EventSubscriber;
+namespace App\EventSubscriber\LogSystem;
 
 
 use App\Entity\LogSystem\SecurityEventLogEntry;
@@ -29,6 +29,10 @@ use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\RequestStack;
 
+/**
+ * This subscriber writes entries to log if an security related event happens (e.g. the user changes its password).
+ * @package App\EventSubscriber\LogSystem
+ */
 final class SecurityEventLoggerSubscriber implements EventSubscriberInterface
 {
 
diff --git a/src/EventSubscriber/MailFromListener.php b/src/EventSubscriber/SetMailFromSubscriber.php
similarity index 92%
rename from src/EventSubscriber/MailFromListener.php
rename to src/EventSubscriber/SetMailFromSubscriber.php
index 5bde6b5c..71d96a03 100644
--- a/src/EventSubscriber/MailFromListener.php
+++ b/src/EventSubscriber/SetMailFromSubscriber.php
@@ -47,7 +47,11 @@ use Symfony\Component\Mailer\Event\MessageEvent;
 use Symfony\Component\Mime\Address;
 use Symfony\Component\Mime\Email;
 
-final class MailFromListener implements EventSubscriberInterface
+/**
+ * This subscriber set the "From" field for all sent email, based on the global configured sender name and email.
+ * @package App\EventSubscriber
+ */
+final class SetMailFromSubscriber implements EventSubscriberInterface
 {
     private $email;
     private $name;
diff --git a/src/EventSubscriber/SymfonyDebugToolbarSubscriber.php b/src/EventSubscriber/SymfonyDebugToolbarSubscriber.php
index e132bd18..377c9633 100644
--- a/src/EventSubscriber/SymfonyDebugToolbarSubscriber.php
+++ b/src/EventSubscriber/SymfonyDebugToolbarSubscriber.php
@@ -47,6 +47,10 @@ use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
 use Symfony\Component\HttpKernel\Event\ResponseEvent;
 
+/**
+ * This subscriber sets an Header in Debug mode that signals the Symfony Profiler to also update on Ajax requests.
+ * @package App\EventSubscriber
+ */
 final class SymfonyDebugToolbarSubscriber implements EventSubscriberInterface
 {
     private $kernel_debug;
diff --git a/src/EventSubscriber/LoginSuccessListener.php b/src/EventSubscriber/UserSystem/LoginSuccessSubscriber.php
similarity index 96%
rename from src/EventSubscriber/LoginSuccessListener.php
rename to src/EventSubscriber/UserSystem/LoginSuccessSubscriber.php
index b2bcc07c..30bacb57 100644
--- a/src/EventSubscriber/LoginSuccessListener.php
+++ b/src/EventSubscriber/UserSystem/LoginSuccessSubscriber.php
@@ -40,7 +40,7 @@ declare(strict_types=1);
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-namespace App\EventSubscriber;
+namespace App\EventSubscriber\UserSystem;
 
 use App\Entity\LogSystem\UserLoginLogEntry;
 use App\Entity\UserSystem\User;
@@ -52,9 +52,9 @@ use Symfony\Component\Security\Http\SecurityEvents;
 use Symfony\Contracts\Translation\TranslatorInterface;
 
 /**
- * This event listener shows an login successful flash to the user after login.
+ * This event listener shows an login successful flash to the user after login and write the login to event log.
  */
-final class LoginSuccessListener implements EventSubscriberInterface
+final class LoginSuccessSubscriber implements EventSubscriberInterface
 {
     private $translator;
     private $flashBag;
diff --git a/src/EventSubscriber/LogoutOnDisabledUserListener.php b/src/EventSubscriber/UserSystem/LogoutDisabledUserSubscriber.php
similarity index 92%
rename from src/EventSubscriber/LogoutOnDisabledUserListener.php
rename to src/EventSubscriber/UserSystem/LogoutDisabledUserSubscriber.php
index 7b1d07f7..565aa907 100644
--- a/src/EventSubscriber/LogoutOnDisabledUserListener.php
+++ b/src/EventSubscriber/UserSystem/LogoutDisabledUserSubscriber.php
@@ -40,7 +40,7 @@ declare(strict_types=1);
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-namespace App\EventSubscriber;
+namespace App\EventSubscriber\UserSystem;
 
 use App\Entity\UserSystem\User;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
@@ -50,7 +50,12 @@ use Symfony\Component\HttpKernel\KernelEvents;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
 use Symfony\Component\Security\Core\Security;
 
-final class LogoutOnDisabledUserListener implements EventSubscriberInterface
+/**
+ * This subscriber is used to log out a disabled user, as soon as he to do an request.
+ * It is not possible for him to login again, afterwards.
+ * @package App\EventSubscriber\UserSystem
+ */
+final class LogoutDisabledUserSubscriber implements EventSubscriberInterface
 {
     private $security;
     private $urlGenerator;
diff --git a/src/EventSubscriber/PasswordChangeNeededSubscriber.php b/src/EventSubscriber/UserSystem/PasswordChangeNeededSubscriber.php
similarity index 99%
rename from src/EventSubscriber/PasswordChangeNeededSubscriber.php
rename to src/EventSubscriber/UserSystem/PasswordChangeNeededSubscriber.php
index 15a891a4..8f3b8426 100644
--- a/src/EventSubscriber/PasswordChangeNeededSubscriber.php
+++ b/src/EventSubscriber/UserSystem/PasswordChangeNeededSubscriber.php
@@ -40,7 +40,7 @@ declare(strict_types=1);
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-namespace App\EventSubscriber;
+namespace App\EventSubscriber\UserSystem;
 
 use App\Entity\UserSystem\User;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
diff --git a/src/EventSubscriber/U2FRegistrationSubscriber.php b/src/EventSubscriber/UserSystem/RegisterU2FSubscriber.php
similarity index 94%
rename from src/EventSubscriber/U2FRegistrationSubscriber.php
rename to src/EventSubscriber/UserSystem/RegisterU2FSubscriber.php
index 78092b66..3e520ecf 100644
--- a/src/EventSubscriber/U2FRegistrationSubscriber.php
+++ b/src/EventSubscriber/UserSystem/RegisterU2FSubscriber.php
@@ -40,7 +40,7 @@ declare(strict_types=1);
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-namespace App\EventSubscriber;
+namespace App\EventSubscriber\UserSystem;
 
 use App\Entity\UserSystem\U2FKey;
 use App\Entity\UserSystem\User;
@@ -55,7 +55,11 @@ use Symfony\Component\HttpFoundation\Session\Flash\FlashBagInterface;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
 use Symfony\Contracts\EventDispatcher\EventDispatcherInterface;
 
-final class U2FRegistrationSubscriber implements EventSubscriberInterface
+/**
+ * This subscriber is used to write U2F keys to DB, after user added them via GUI.
+ * @package App\EventSubscriber\UserSystem
+ */
+final class RegisterU2FSubscriber implements EventSubscriberInterface
 {
     private $em;
 
diff --git a/src/EventSubscriber/TimezoneListener.php b/src/EventSubscriber/UserSystem/SetUserTimezoneSubscriber.php
similarity index 97%
rename from src/EventSubscriber/TimezoneListener.php
rename to src/EventSubscriber/UserSystem/SetUserTimezoneSubscriber.php
index 52257319..c4af39e2 100644
--- a/src/EventSubscriber/TimezoneListener.php
+++ b/src/EventSubscriber/UserSystem/SetUserTimezoneSubscriber.php
@@ -40,7 +40,7 @@ declare(strict_types=1);
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
-namespace App\EventSubscriber;
+namespace App\EventSubscriber\UserSystem;
 
 use App\Entity\UserSystem\User;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
@@ -51,7 +51,7 @@ use Symfony\Component\Security\Core\Security;
 /**
  * The purpose of this event listener is to set the timezone to the one preferred by the user.
  */
-final class TimezoneListener implements EventSubscriberInterface
+final class SetUserTimezoneSubscriber implements EventSubscriberInterface
 {
     private $default_timezone;
     private $security;
diff --git a/tests/EventSubscriber/PasswordChangeNeededSubscriberTest.php b/tests/EventSubscriber/PasswordChangeNeededSubscriberTest.php
index d09cb000..916ca5c1 100644
--- a/tests/EventSubscriber/PasswordChangeNeededSubscriberTest.php
+++ b/tests/EventSubscriber/PasswordChangeNeededSubscriberTest.php
@@ -45,7 +45,7 @@ namespace App\Tests\EventSubscriber;
 use App\Entity\UserSystem\Group;
 use App\Entity\UserSystem\U2FKey;
 use App\Entity\UserSystem\User;
-use App\EventSubscriber\PasswordChangeNeededSubscriber;
+use App\EventSubscriber\UserSystem\PasswordChangeNeededSubscriber;
 use PHPUnit\Framework\TestCase;
 
 class PasswordChangeNeededSubscriberTest extends TestCase
@@ -57,11 +57,11 @@ class PasswordChangeNeededSubscriberTest extends TestCase
 
         //A user without a group must not redirect
         $user->setGroup(null);
-        $this->assertFalse(PasswordChangeNeededSubscriber::TFARedirectNeeded($user));
+        $this->assertFalse(\App\EventSubscriber\UserSystem\PasswordChangeNeededSubscriber::TFARedirectNeeded($user));
 
         //When the group does not enforce the redirect the user must not be redirected
         $user->setGroup($group);
-        $this->assertFalse(PasswordChangeNeededSubscriber::TFARedirectNeeded($user));
+        $this->assertFalse(\App\EventSubscriber\UserSystem\PasswordChangeNeededSubscriber::TFARedirectNeeded($user));
 
         //The user must be redirected if the group enforces 2FA and it does not have a method
         $group->setEnforce2FA(true);