diff --git a/.gitignore b/.gitignore
index e9adf39..fd51142 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@ composer.lock
 .phpunit.result.cache
 node_modules/
 package-lock.json
+.phpdoc
diff --git a/docs/README.md b/docs/README.md
new file mode 100644
index 0000000..9ac1310
--- /dev/null
+++ b/docs/README.md
@@ -0,0 +1,71 @@
+## Developer documentation
+
+### Overview
+
+The entry point of the plugin is the initialization of the singleton class `\Event_Bridge_For_ActivityPub\Setup` in the main plugin file `event-bridge-for-activitypub.php`.
+The constructor of that class calls its `setup_hooks()` function. This function provides hooks that initialize all parts of the _Event Bridge For ActivityPub_ whenever needed.
+
+### File structure
+
+Note that almost all files and folder within the `activitypub` folders are structured the same way as in the WordPress ActivityPub plugin.
+
+### Event Plugin Integrations
+
+This plugin supports multiple event plugins, even at the same time. To add a new one you first need to add some basic information about your event plugin. Just create a new file in `./includes/integrations/my-event-plugin.php`. Implement at least all abstract functions of the `Event_Plugin_Integration` class.
+
+#### Basic Event Plugin Integration
+
+```php
+  namespace Event_Bridge_For_ActivityPub\Integrations;
+
+  // Exit if accessed directly.
+  defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+  /**
+   * Integration information for My Event Plugin
+   *
+   * This class defines necessary meta information is for the integration of My Event Plugin with the ActivityPub plugin.
+   */
+  final class My_Event_Plugin extends Event_Plugin_Integration {
+```
+
+#### Registering an Event Plugin Integration
+
+Then you need to tell the Event Bridge for ActivityPub about that class by adding it to the `EVENT_PLUGIN_INTEGRATIONS` constant in the `includes/setup.php` file:
+
+```php
+	private const EVENT_PLUGIN_INTEGRATIONS = array(
+		...
+		\Event_Bridge_For_ActivityPub\Integrations\My_Event_Plugin::class,
+	);
+```
+
+#### Additional Feature: Event Sources
+
+Not all _Event Plugin Integrations_ support the event-sources feature. To add support for it an integration must implement the `Feature_Event_Sources` interface.
+
+```php
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+  /**
+   * Integration information for My Event Plugin.
+   *
+   * This class defines necessary meta information is for the integration of My Event Plugin with the ActivityPub plugin.
+   * This integration supports the Event Sources Feature.
+   */
+final class GatherPress extends Event_Plugin_Integration implements Feature_Event_Sources {
+```
+
+### Transformer
+
+Transformers are the classes that convert an WordPress post type (e.g. one used for events) to _ActivityStreams_.
+The Event Bridge for ActivityPub then takes care of applying the transformer, so you can jump right into [implementing it](./implement_an_activitypub_event_transformer.md).
+
+### Event Sources Feature – Transmogrifier
+
+The event sources feature allows to aggregate events from external ActivityPub actors. As the initialization of the Event-Sources feature is quite complex all of that initialization is done in the `init` function of the file `includes/class-event-sources.php` which is called by the `\Event_Bridge_For_ActivityPub\Setup` class (`includes/class-setup.php`).
+
+In this plugin we call a **_Transmogrifier_** the **opposite** of a **_Transformer_**. It takes care of converting an ActivityPub (`Event`) object in _ActivityStreams_ to the WordPress representation of an event plugin. The transmogrifier classes are only used when the `Event Sources` feature is activated. The _Event Bridge For ActivityPub_ can register transformers for multiple event plugins at the same time, however only one transmogrifier, that is one target even plugin can be used as a target for incoming external ActivityPub `Event` objects.
diff --git a/docs/event_plugin_integrations.md b/docs/event_plugin_integrations.md
new file mode 100644
index 0000000..e654184
--- /dev/null
+++ b/docs/event_plugin_integrations.md
@@ -0,0 +1,50 @@
+
+## Event Plugin Integrations
+
+First you need to add some basic information about your event plugin. Just create a new file in `./includes/integrations/my-event-plugin.php`. Implement at least all abstract functions of the `Event_Plugin_Integration` class.
+
+### Basic Event Plugin Integration
+
+```php
+  namespace Event_Bridge_For_ActivityPub\Integrations;
+
+  // Exit if accessed directly.
+  defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+  /**
+   * Integration information for My Event Plugin
+   *
+   * This class defines necessary meta information is for the integration of My Event Plugin with the ActivityPub plugin.
+   */
+  final class My_Event_Plugin extends Event_Plugin_Integration {
+```
+
+### Registering an Event Plugin Integration
+
+Then you need to tell the Event Bridge for ActivityPub about that class by adding it to the `EVENT_PLUGIN_INTEGRATIONS` constant in the `includes/setup.php` file:
+
+```php
+	private const EVENT_PLUGIN_INTEGRATIONS = array(
+		...
+		\Event_Bridge_For_ActivityPub\Integrations\My_Event_Plugin::class,
+	);
+```
+
+### Additional Feature: Event Sources
+
+Not all _Event Plugin Integrations_ support the event-sources feature. To add support for it an integration must implement the `Feature_Event_Sources` interface.
+
+```php
+namespace Event_Bridge_For_ActivityPub\Integrations;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+  /**
+   * Integration information for My Event Plugin.
+   *
+   * This class defines necessary meta information is for the integration of My Event Plugin with the ActivityPub plugin.
+   * This integration supports the Event Sources Feature.
+   */
+final class GatherPress extends Event_Plugin_Integration implements Feature_Event_Sources {
+```
diff --git a/docs/add_your_event_plugin.md b/docs/transformer.md
similarity index 88%
rename from docs/add_your_event_plugin.md
rename to docs/transformer.md
index 3b79f84..333e17e 100644
--- a/docs/add_your_event_plugin.md
+++ b/docs/transformer.md
@@ -2,43 +2,12 @@
 
 > **_NOTE:_** This documentation is also likely to be useful for content types other than events.
 
-The ActivityPub plugin offers a basic support for all post types out of the box, but it also allows the registration of external transformers. A transformer is a class that implements the [abstract transformer class](https://github.com/Automattic/wordpress-activitypub/blob/fb0e23e8854d149fdedaca7a9ea856f5fd965ec9/includes/transformer/class-base.php) and is responsible for generating the ActivityPub JSON representation of an WordPress post or comment object. 
+The ActivityPub plugin offers a basic support for all post types out of the box, but it also allows the registration of external transformers. A transformer is a class that implements the [abstract transformer class](https://github.com/Automattic/wordpress-activitypub/blob/fb0e23e8854d149fdedaca7a9ea856f5fd965ec9/includes/transformer/class-base.php) and is responsible for generating the ActivityPub JSON representation of an WordPress post or comment object.
 
 ## How it works
 
 To make the WordPress ActivityPub plugin use a custom transformer simply add a filter to the `activitypub_transformer` hook which provides access to the transformer factory. The [transformer factory](https://github.com/Automattic/wordpress-activitypub/blob/master/includes/transformer/class-factory.php#L12) determines which transformer is used to transform a WordPress object to ActivityPub. We provide a parent event transformer, that comes with common tasks needed for events. Furthermore, we provide admin notices, to prevent users from misconfiguration issues.
 
-## Add your event plugin
-
-First you need to add some basic information about your event plugin. Just create a new file in `./includes/plugins/my-event-plugin.php`. Implement at least all abstract functions of the `Event_Plugin` class.
-
-```php
-  namespace Event_Bridge_For_ActivityPub\Integrations;
-
-  // Exit if accessed directly.
-  defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
-
-  /**
-   * Integration information for My Event Plugin
-   *
-   * This class defines necessary meta information is for the integration of My Event Plugin with the ActivityPub plugin.
-   *
-   * @since 1.0.0
-   */
-  final class My_Event_Plugin extends Event_Plugin {
-```
-
-Then you need to tell the Event Bridge for ActivityPub about that class by adding it to the `EVENT_PLUGIN_INTEGRATIONS` constant in the `includes/setup.php` file:
-
-```php
-	private const EVENT_PLUGIN_INTEGRATIONS = array(
-		...
-		'\Event_Bridge_For_ActivityPub\Integrations\My_Event_Plugin',
-	);
-```
-
-The Event Bridge for ActivityPub then takes care of applying the transformer, so you can jump right into implementing it.
-
 ## Writing an event transformer class
 
 Within WordPress most content types are stored as a custom post type in the posts table. The ActivityPub plugin offers a basic support for all post types out of the box. So-called transformers take care of converting WordPress WP_Post objects to ActivityStreams JSON. The ActivityPub plugin offers a generic transformer for all post types. Additionally, custom transformers can be implemented to better fit a custom post type, and they can be easily registered with the ActivityPub plugin.
@@ -48,9 +17,9 @@ If you are writing a transformer for your event post type we recommend to start
 So create a new file at `./includes/activitypub/transformer/my-event-plugin.php`.
 
 ```php
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event as Event_Transformer;
 
 /**
  * ActivityPub Transformer for My Event Plugin' event post type.
diff --git a/includes/activitypub/class-handler.php b/includes/activitypub/class-handler.php
index 0fa1433..47a6f7c 100644
--- a/includes/activitypub/class-handler.php
+++ b/includes/activitypub/class-handler.php
@@ -12,6 +12,9 @@ namespace Event_Bridge_For_ActivityPub\ActivityPub;
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
+use DateTime;
+use DateTimeZone;
+use Event_Bridge_For_ActivityPub\ActivityPub\Collection\Event_Sources;
 use Event_Bridge_For_ActivityPub\ActivityPub\Handler\Accept;
 use Event_Bridge_For_ActivityPub\ActivityPub\Handler\Update;
 use Event_Bridge_For_ActivityPub\ActivityPub\Handler\Create;
@@ -29,5 +32,94 @@ class Handler {
 		Update::init();
 		Create::init();
 		Delete::init();
+		\add_filter(
+			'activitypub_validate_object',
+			array( self::class, 'validate_object' ),
+			12,
+			3
+		);
+	}
+
+
+	/**
+	 * Validate the object.
+	 *
+	 * @param bool             $valid   The validation state.
+	 * @param string           $param   The object parameter.
+	 * @param \WP_REST_Request $request The request object.
+	 *
+	 * @return bool The validation state: true if valid, false if not.
+	 */
+	public static function validate_object( $valid, $param, $request ) {
+		$json_params = $request->get_json_params();
+
+		if ( isset( $json_params['object']['type'] ) && 'Event' === $json_params['object']['type'] ) {
+			$valid = true;
+		} else {
+			return $valid;
+		}
+
+		if ( empty( $json_params['type'] ) ) {
+			return false;
+		}
+
+		if ( empty( $json_params['actor'] ) ) {
+			return false;
+		}
+
+		if ( ! in_array( $json_params['type'], array( 'Create', 'Update', 'Delete', 'Announce' ), true ) || is_wp_error( $request ) ) {
+			return $valid;
+		}
+
+		$object = $json_params['object'];
+
+		if ( ! is_array( $object ) ) {
+			return false;
+		}
+
+		$required = array(
+			'id',
+			'startTime',
+			'name',
+		);
+
+		if ( array_intersect( $required, array_keys( $object ) ) !== $required ) {
+			return false;
+		}
+
+		return $valid;
+	}
+
+	/**
+	 * Check if a given DateTime is already passed.
+	 *
+	 * @param string $time_string The ActivityPub like time string.
+	 * @return bool
+	 */
+	public static function is_time_passed( $time_string ) {
+		// Create a DateTime object from the ActivityPub time string.
+		$time = new DateTime( $time_string, new DateTimeZone( 'UTC' ) );
+
+		// Get the current time in UTC.
+		$current_time = new DateTime( 'now', new DateTimeZone( 'UTC' ) );
+
+		// Compare the event time with the current time.
+		return $time < $current_time;
+	}
+
+	/**
+	 * Check that an ActivityPub actor is an event source (i.e. it is followed by the ActivityPub blog actor).
+	 *
+	 * @param string $actor_id The actor ID.
+	 * @return bool True if the ActivityPub actor ID is followed, false otherwise.
+	 */
+	public static function actor_is_event_source( $actor_id ) {
+		$event_sources = Event_Sources::get_event_sources();
+		foreach ( $event_sources as $event_source ) {
+			if ( $actor_id === $event_source->get_id() ) {
+				return true;
+			}
+		}
+		return false;
 	}
 }
diff --git a/includes/activitypub/collection/class-event-sources.php b/includes/activitypub/collection/class-event-sources.php
index 79a5a93..b3fb37e 100644
--- a/includes/activitypub/collection/class-event-sources.php
+++ b/includes/activitypub/collection/class-event-sources.php
@@ -1,6 +1,17 @@
 <?php
 /**
- * Event sources collection file.
+ * ActivityPub Event Sources (=Followed Actors) Collection.
+ *
+ * The Event Sources are nothing else than follows in the ActivityPub world.
+ * However, this plugins currently only listens to Event object being created,
+ * updated or deleted by a follow.
+ *
+ * For the ActivityPub `Follow` the Blog-Actor from the ActivityPub plugin is used.
+ *
+ * This class is responsible for defining a custom post type in WordPress along
+ * with post-meta fields and methods to easily manage event sources. This includes
+ * handling side effects, like when an event source is added a follow request is sent
+ * or adding them to the `follow` collection o the blog-actor profile.
  *
  * @package Event_Bridge_For_ActivityPub
  * @since 1.0.0
@@ -19,6 +30,17 @@ use function Activitypub\get_remote_metadata_by_actor;
 
 /**
  * ActivityPub Event Sources (=Followed Actors) Collection.
+ *
+ * The Event Sources are nothing else than follows in the ActivityPub world.
+ * However, this plugins currently only listens to Event object being created,
+ * updated or deleted by a follow.
+ *
+ * For the ActivityPub `Follow` the Blog-Actor from the ActivityPub plugin is used.
+ *
+ * This class is responsible for defining a custom post type in WordPress along
+ * with post-meta fields and methods to easily manage event sources. This includes
+ * handling side effects, like when an event source is added a follow request is sent
+ * or adding them to the `follow` collection o the blog-actor profile.
  */
 class Event_Sources {
 	/**
diff --git a/includes/activitypub/handler/class-accept.php b/includes/activitypub/handler/class-accept.php
index c246df9..9e3aa2e 100644
--- a/includes/activitypub/handler/class-accept.php
+++ b/includes/activitypub/handler/class-accept.php
@@ -15,7 +15,7 @@ use Activitypub\Collection\Actors;
  */
 class Accept {
 	/**
-	 * Initialize the class, registering WordPress hooks.
+	 * Initialize the class, registering the handler for incoming `Accept` activities to the ActivityPub plugin.
 	 */
 	public static function init() {
 		\add_action(
@@ -25,7 +25,7 @@ class Accept {
 	}
 
 	/**
-	 * Handle "Follow" requests.
+	 * Handle incoming "Accept" activities.
 	 *
 	 * @param array $activity The activity object.
 	 */
diff --git a/includes/activitypub/handler/class-create.php b/includes/activitypub/handler/class-create.php
index f83e42a..04b77e7 100644
--- a/includes/activitypub/handler/class-create.php
+++ b/includes/activitypub/handler/class-create.php
@@ -8,10 +8,8 @@
 namespace Event_Bridge_For_ActivityPub\ActivityPub\Handler;
 
 use Activitypub\Collection\Actors;
-use DateTime;
-use DateTimeZone;
-use Event_Bridge_For_ActivityPub\ActivityPub\Collection\Event_Sources;
 use Event_Bridge_For_ActivityPub\Setup;
+use Event_Bridge_For_ActivityPub\ActivityPub\Handler;
 
 use function Activitypub\is_activity_public;
 
@@ -20,7 +18,7 @@ use function Activitypub\is_activity_public;
  */
 class Create {
 	/**
-	 * Initialize the class, registering WordPress hooks.
+	 * Initialize the class, registering the handler for incoming `Create` activities to the ActivityPub plugin.
 	 */
 	public static function init() {
 		\add_action(
@@ -29,16 +27,10 @@ class Create {
 			15,
 			2
 		);
-		\add_filter(
-			'activitypub_validate_object',
-			array( self::class, 'validate_object' ),
-			12,
-			3
-		);
 	}
 
 	/**
-	 * Handle "Create" requests.
+	 * Handle incoming "Create" activities.
 	 *
 	 * @param array $activity The activity-object.
 	 * @param int   $user_id  The id of the local blog-user.
@@ -49,7 +41,7 @@ class Create {
 			return;
 		}
 
-		if ( ! self::actor_is_event_source( $activity['actor'] ) ) {
+		if ( ! Handler::actor_is_event_source( $activity['actor'] ) ) {
 			return;
 		}
 
@@ -63,7 +55,7 @@ class Create {
 			return;
 		}
 
-		if ( self::is_time_passed( $activity['object']['startTime'] ) ) {
+		if ( Handler::is_time_passed( $activity['object']['startTime'] ) ) {
 			return;
 		}
 
@@ -75,86 +67,4 @@ class Create {
 
 		$transmogrifier->save( $activity['object'] );
 	}
-
-	/**
-	 * Validate the object.
-	 *
-	 * @param bool             $valid   The validation state.
-	 * @param string           $param   The object parameter.
-	 * @param \WP_REST_Request $request The request object.
-	 *
-	 * @return bool The validation state: true if valid, false if not.
-	 */
-	public static function validate_object( $valid, $param, $request ) {
-		$json_params = $request->get_json_params();
-
-		if ( isset( $json_params['object']['type'] ) && 'Event' === $json_params['object']['type'] ) {
-			$valid = true;
-		} else {
-			return $valid;
-		}
-
-		if ( empty( $json_params['type'] ) ) {
-			return false;
-		}
-
-		if ( empty( $json_params['actor'] ) ) {
-			return false;
-		}
-
-		if ( ! in_array( $json_params['type'], array( 'Create', 'Update', 'Delete', 'Announce' ), true ) || is_wp_error( $request ) ) {
-			return $valid;
-		}
-
-		$object = $json_params['object'];
-
-		if ( ! is_array( $object ) ) {
-			return false;
-		}
-
-		$required = array(
-			'id',
-			'startTime',
-			'name',
-		);
-
-		if ( array_intersect( $required, array_keys( $object ) ) !== $required ) {
-			return false;
-		}
-
-		return $valid;
-	}
-
-	/**
-	 * Check if a given DateTime is already passed.
-	 *
-	 * @param string $time_string The ActivityPub like time string.
-	 * @return bool
-	 */
-	private static function is_time_passed( $time_string ) {
-		// Create a DateTime object from the ActivityPub time string.
-		$time = new DateTime( $time_string, new DateTimeZone( 'UTC' ) );
-
-		// Get the current time in UTC.
-		$current_time = new DateTime( 'now', new DateTimeZone( 'UTC' ) );
-
-		// Compare the event time with the current time.
-		return $time < $current_time;
-	}
-
-	/**
-	 * Check if an ActivityPub actor is an event source.
-	 *
-	 * @param string $actor_id The actor ID.
-	 * @return bool
-	 */
-	public static function actor_is_event_source( $actor_id ) {
-		$event_sources = Event_Sources::get_event_sources();
-		foreach ( $event_sources as $event_source ) {
-			if ( $actor_id === $event_source->get_id() ) {
-				return true;
-			}
-		}
-		return false;
-	}
 }
diff --git a/includes/activitypub/handler/class-delete.php b/includes/activitypub/handler/class-delete.php
index 9fa2224..ae8eb8f 100644
--- a/includes/activitypub/handler/class-delete.php
+++ b/includes/activitypub/handler/class-delete.php
@@ -9,13 +9,14 @@ namespace Event_Bridge_For_ActivityPub\ActivityPub\Handler;
 
 use Activitypub\Collection\Actors;
 use Event_Bridge_For_ActivityPub\Setup;
+use Event_Bridge_For_ActivityPub\ActivityPub\Handler;
 
 /**
  * Handle Delete requests.
  */
 class Delete {
 	/**
-	 * Initialize the class, registering WordPress hooks.
+	 * Initialize the class, registering the handler for incoming `Delete` activities to the ActivityPub plugin.
 	 */
 	public static function init() {
 		\add_action(
@@ -38,7 +39,7 @@ class Delete {
 			return;
 		}
 
-		if ( ! Create::actor_is_event_source( $activity['actor'] ) ) {
+		if ( ! Handler::actor_is_event_source( $activity['actor'] ) ) {
 			return;
 		}
 
@@ -47,6 +48,10 @@ class Delete {
 			return;
 		}
 
+		if ( Handler::is_time_passed( $activity['object']['startTime'] ) ) {
+			return;
+		}
+
 		$transmogrifier = Setup::get_transmogrifier();
 
 		if ( ! $transmogrifier ) {
diff --git a/includes/activitypub/handler/class-update.php b/includes/activitypub/handler/class-update.php
index 06d046d..bbc918f 100644
--- a/includes/activitypub/handler/class-update.php
+++ b/includes/activitypub/handler/class-update.php
@@ -9,6 +9,7 @@ namespace Event_Bridge_For_ActivityPub\ActivityPub\Handler;
 
 use Activitypub\Collection\Actors;
 use Event_Bridge_For_ActivityPub\Setup;
+use Event_Bridge_For_ActivityPub\ActivityPub\Handler;
 
 use function Activitypub\is_activity_public;
 
@@ -17,7 +18,7 @@ use function Activitypub\is_activity_public;
  */
 class Update {
 	/**
-	 * Initialize the class, registering WordPress hooks.
+	 * Initialize the class, registering the handler for incoming `Update` activities to the ActivityPub plugin.
 	 */
 	public static function init() {
 		\add_action(
@@ -29,17 +30,21 @@ class Update {
 	}
 
 	/**
-	 * Handle "Follow" requests.
+	 * Handle incoming "Update" activities..
 	 *
 	 * @param array $activity The activity-object.
 	 * @param int   $user_id  The id of the local blog-user.
 	 */
 	public static function handle_update( $activity, $user_id ) {
-		// We only process activities that are target the application user.
+		// We only process activities that are target to the application user.
 		if ( Actors::BLOG_USER_ID !== $user_id ) {
 			return;
 		}
 
+		if ( ! Handler::actor_is_event_source( $activity['actor'] ) ) {
+			return;
+		}
+
 		// Check if Activity is public or not.
 		if ( ! is_activity_public( $activity ) ) {
 			return;
@@ -50,6 +55,10 @@ class Update {
 			return;
 		}
 
+		if ( Handler::is_time_passed( $activity['object']['startTime'] ) ) {
+			return;
+		}
+
 		$transmogrifier = Setup::get_transmogrifier();
 
 		if ( ! $transmogrifier ) {
diff --git a/includes/activitypub/model/class-event-source.php b/includes/activitypub/model/class-event-source.php
index 800a82b..df9d882 100644
--- a/includes/activitypub/model/class-event-source.php
+++ b/includes/activitypub/model/class-event-source.php
@@ -2,6 +2,10 @@
 /**
  * Event-Source (=ActivityPub Actor that is followed) model.
  *
+ * This class holds methods needed for relating an ActivityPub actor
+ * that is followed with the custom post type structure how it is
+ * stored within WordPress.
+ *
  * @package Event_Bridge_For_ActivityPub
  * @license AGPL-3.0-or-later
  */
@@ -16,6 +20,10 @@ use function Activitypub\sanitize_url;
 
 /**
  * Event-Source (=ActivityPub Actor that is followed) model.
+ *
+ * This class holds methods needed for relating an ActivityPub actor
+ * that is followed with the custom post type structure how it is
+ * stored within WordPress.
  */
 class Event_Source extends Actor {
 	const ACTIVITYPUB_USER_HANDLE_REGEXP = '(?:([A-Za-z0-9_.-]+)@((?:[A-Za-z0-9_-]+\.)+[A-Za-z]+))';
diff --git a/includes/activitypub/transformer/class-event-organiser.php b/includes/activitypub/transformer/class-event-organiser.php
index 6574f54..7a34b12 100644
--- a/includes/activitypub/transformer/class-event-organiser.php
+++ b/includes/activitypub/transformer/class-event-organiser.php
@@ -6,13 +6,13 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Place;
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event;
 
 /**
  * ActivityPub Transformer for Event Organiser.
diff --git a/includes/activitypub/transformer/class-event.php b/includes/activitypub/transformer/class-event.php
index cb388c2..88c78b3 100644
--- a/includes/activitypub/transformer/class-event.php
+++ b/includes/activitypub/transformer/class-event.php
@@ -6,7 +6,7 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
diff --git a/includes/activitypub/transformer/class-eventin.php b/includes/activitypub/transformer/class-eventin.php
index 7b4131d..f1417e0 100644
--- a/includes/activitypub/transformer/class-eventin.php
+++ b/includes/activitypub/transformer/class-eventin.php
@@ -8,13 +8,13 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Place;
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event;
 use DateTime;
 use DateTimeZone;
 use Etn\Core\Event\Event_Model;
diff --git a/includes/activitypub/transformer/class-eventprime.php b/includes/activitypub/transformer/class-eventprime.php
index c85548e..68a7f0d 100644
--- a/includes/activitypub/transformer/class-eventprime.php
+++ b/includes/activitypub/transformer/class-eventprime.php
@@ -6,13 +6,13 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Place;
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event;
 
 /**
  * ActivityPub Transformer for VS Event
diff --git a/includes/activitypub/transformer/class-events-manager.php b/includes/activitypub/transformer/class-events-manager.php
index 92fbad2..bc84e2e 100644
--- a/includes/activitypub/transformer/class-events-manager.php
+++ b/includes/activitypub/transformer/class-events-manager.php
@@ -6,13 +6,13 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Place;
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event as Event_Transformer;
 use DateTime;
 use DateTimeZone;
 use EM_Event;
diff --git a/includes/activitypub/transformer/class-gatherpress.php b/includes/activitypub/transformer/class-gatherpress.php
index 79eb601..d58dc2b 100644
--- a/includes/activitypub/transformer/class-gatherpress.php
+++ b/includes/activitypub/transformer/class-gatherpress.php
@@ -6,14 +6,14 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Event as Event_Object;
 use Activitypub\Activity\Extended_Object\Place;
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event;
 use GatherPress\Core\Event as GatherPress_Event;
 
 /**
diff --git a/includes/activitypub/transformer/class-modern-events-calendar-lite.php b/includes/activitypub/transformer/class-modern-events-calendar-lite.php
index edff084..3dfbd10 100644
--- a/includes/activitypub/transformer/class-modern-events-calendar-lite.php
+++ b/includes/activitypub/transformer/class-modern-events-calendar-lite.php
@@ -6,13 +6,13 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Place;
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event;
 
 use MEC;
 use MEC\Events\Event as MEC_Event;
diff --git a/includes/activitypub/transformer/class-the-events-calendar.php b/includes/activitypub/transformer/class-the-events-calendar.php
index 880fee3..08aab3f 100644
--- a/includes/activitypub/transformer/class-the-events-calendar.php
+++ b/includes/activitypub/transformer/class-the-events-calendar.php
@@ -6,13 +6,13 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Place;
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event;
 use WP_Post;
 
 use function Activitypub\esc_hashtag;
diff --git a/includes/activitypub/transformer/class-vs-event-list.php b/includes/activitypub/transformer/class-vs-event-list.php
index 42fdb14..329880b 100644
--- a/includes/activitypub/transformer/class-vs-event-list.php
+++ b/includes/activitypub/transformer/class-vs-event-list.php
@@ -6,13 +6,13 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Place;
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event as Event_Transformer;
 
 /**
  * ActivityPub Transformer for VS Event.
diff --git a/includes/activitypub/transformer/class-wp-event-manager.php b/includes/activitypub/transformer/class-wp-event-manager.php
index 7985291..aec0d58 100644
--- a/includes/activitypub/transformer/class-wp-event-manager.php
+++ b/includes/activitypub/transformer/class-wp-event-manager.php
@@ -6,13 +6,13 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transformer;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 use Activitypub\Activity\Extended_Object\Place;
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as Event_Transformer;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event as Event_Transformer;
 use DateTime;
 
 /**
diff --git a/includes/activitypub/transmogrifier/class-base.php b/includes/activitypub/transmogrifier/class-base.php
index b32d264..6f399ae 100644
--- a/includes/activitypub/transmogrifier/class-base.php
+++ b/includes/activitypub/transmogrifier/class-base.php
@@ -7,7 +7,7 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transmogrifier;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier;
 
 use Activitypub\Activity\Extended_Object\Event;
 use DateTime;
diff --git a/includes/activitypub/transmogrifier/class-gatherpress.php b/includes/activitypub/transmogrifier/class-gatherpress.php
index 78128c6..9420eb5 100644
--- a/includes/activitypub/transmogrifier/class-gatherpress.php
+++ b/includes/activitypub/transmogrifier/class-gatherpress.php
@@ -9,7 +9,7 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transmogrifier;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier;
 
 use DateTime;
 
diff --git a/includes/activitypub/transmogrifier/class-the-events-calendar-event-repository.php b/includes/activitypub/transmogrifier/class-the-events-calendar-event-repository.php
index 6952087..32c940c 100644
--- a/includes/activitypub/transmogrifier/class-the-events-calendar-event-repository.php
+++ b/includes/activitypub/transmogrifier/class-the-events-calendar-event-repository.php
@@ -7,7 +7,7 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transmogrifier;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier;
 
 use DateTime;
 
diff --git a/includes/activitypub/transmogrifier/class-the-events-calendar.php b/includes/activitypub/transmogrifier/class-the-events-calendar.php
index 4b52457..2106b20 100644
--- a/includes/activitypub/transmogrifier/class-the-events-calendar.php
+++ b/includes/activitypub/transmogrifier/class-the-events-calendar.php
@@ -9,7 +9,7 @@
  * @license AGPL-3.0-or-later
  */
 
-namespace Event_Bridge_For_ActivityPub\Activitypub\Transmogrifier;
+namespace Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier;
 
 use DateTime;
 
diff --git a/includes/class-event-sources.php b/includes/class-event-sources.php
index 8b8f629..7b6d3ff 100644
--- a/includes/class-event-sources.php
+++ b/includes/class-event-sources.php
@@ -11,8 +11,7 @@ namespace Event_Bridge_For_ActivityPub;
 
 use Activitypub\Model\Blog;
 use Event_Bridge_For_ActivityPub\ActivityPub\Collection\Event_Sources as Event_Sources_Collection;
-use Event_Bridge_For_ActivityPub\Activitypub\Transmogrifier\GatherPress;
-use Event_Bridge_For_ActivityPub\Activitypub\Handler;
+use Event_Bridge_For_ActivityPub\ActivityPub\Handler;
 use Event_Bridge_For_ActivityPub\Admin\User_Interface;
 use Event_Bridge_For_ActivityPub\Integrations\Event_Plugin_Integration;
 use Event_Bridge_For_ActivityPub\Integrations\Feature_Event_Sources;
@@ -30,17 +29,30 @@ class Event_Sources {
 	 * Init.
 	 */
 	public static function init() {
+		// Register the Event Sources Collection which takes care of managing the event sources.
 		\add_action( 'init', array( Event_Sources_Collection::class, 'init' ) );
+
+		// Register handlers for incoming activities to the ActivityPub plugin, e.g. incoming `Event` objects.
 		\add_action( 'activitypub_register_handlers', array( Handler::class, 'register_handlers' ) );
+
+		// Apply modifications to the UI, e.g. disable editing of remote event posts.
 		\add_action( 'init', array( User_Interface::class, 'init' ) );
+
+		// Register post meta to the event plugins post types needed for easier handling of this feature.
 		\add_action( 'init', array( self::class, 'register_post_meta' ) );
+
+		// Register filters that prevent cached remote events from being federated again.
 		\add_filter( 'activitypub_is_post_disabled', array( self::class, 'is_cached_external_post' ), 10, 2 );
+		\add_filter( 'template_include', array( self::class, 'redirect_activitypub_requests_for_cached_external_events' ), 100 );
+
+		// Register daily schedule to cleanup cached remote events that have ended.
 		if ( ! \wp_next_scheduled( 'event_bridge_for_activitypub_event_sources_clear_cache' ) ) {
 			\wp_schedule_event( time(), 'daily', 'event_bridge_for_activitypub_event_sources_clear_cache' );
 		}
 		\add_action( 'event_bridge_for_activitypub_event_sources_clear_cache', array( self::class, 'clear_cache' ) );
+
+		// Add the actors followed by the event sources feature to the `follow` collection of the used ActivityPub actor.
 		\add_filter( 'activitypub_rest_following', array( self::class, 'add_event_sources_to_following_collection' ), 10, 2 );
-		\add_filter( 'template_include', array( self::class, 'redirect_activitypub_requests_for_cached_external_events' ), 100 );
 	}
 
 
diff --git a/includes/class-setup.php b/includes/class-setup.php
index d74aab5..364dbcb 100644
--- a/includes/class-setup.php
+++ b/includes/class-setup.php
@@ -64,14 +64,6 @@ class Setup {
 	 * @since 1.0.0
 	 */
 	protected function __construct() {
-		$this->activitypub_plugin_is_active = defined( 'ACTIVITYPUB_PLUGIN_VERSION' ) ||
-			is_plugin_active( 'activitypub/activitypub.php' );
-		// BeforeFirstRelease: decide whether we want to do anything at all when ActivityPub plugin is note active.
-		// if ( ! $this->activitypub_plugin_is_active ) {
-		// deactivate_plugins( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE );
-		// return;
-		// }.
-		$this->activitypub_plugin_version = self::get_activitypub_plugin_version();
 		add_action( 'plugins_loaded', array( $this, 'setup_hooks' ) );
 	}
 
@@ -204,7 +196,7 @@ class Setup {
 	}
 
 	/**
-	 * Set up hooks for various purposes.
+	 * Main setup function of the plugin "Event Bridge For ActivityPub".
 	 *
 	 * This method adds hooks for different purposes as needed.
 	 *
@@ -213,16 +205,30 @@ class Setup {
 	 * @return void
 	 */
 	public function setup_hooks(): void {
+		// Detect the presence of the ActivityPub plugin.
+		$this->activitypub_plugin_is_active = defined( 'ACTIVITYPUB_PLUGIN_VERSION' ) && \is_plugin_active( 'activitypub/activitypub.php' );
+		$this->activitypub_plugin_version   = self::get_activitypub_plugin_version();
+
+		// Detect active supported event plugins.
 		$this->detect_active_event_plugins();
 
+		// Register self-activation hook.
 		register_activation_hook( EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_FILE, array( $this, 'activate' ) );
 
+		// Register listeners whenever any plugin gets activated or deactivated.
 		add_action( 'activated_plugin', array( $this, 'redetect_active_event_plugins' ) );
 		add_action( 'deactivated_plugin', array( $this, 'redetect_active_event_plugins' ) );
 
+		// Add hook that takes care of all notices in the Admin UI.
 		add_action( 'admin_init', array( $this, 'do_admin_notices' ) );
+
+		// Add hook that registers all settings to WordPress.
 		add_action( 'admin_init', array( Settings::class, 'register_settings' ) );
+
+		// Add hook that loads CSS and JavaScript files fr the Admin UI.
 		add_action( 'admin_enqueue_scripts', array( self::class, 'enqueue_styles' ) );
+
+		// Register the settings page(s) of this plugin to WordPress.
 		add_action( 'admin_menu', array( Settings_Page::class, 'admin_menu' ) );
 		add_filter(
 			'plugin_action_links_' . EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_BASENAME,
@@ -234,18 +240,21 @@ class Setup {
 			return;
 		}
 
+		// Register health checks and status reports to the WordPress status report site.
 		add_action( 'init', array( Health_Check::class, 'init' ) );
 
-		// Check if the minimum required version of the ActivityPub plugin is installed.
+		// Check if the minimum required version of the ActivityPub plugin is installed, if not abort.
 		if ( ! version_compare( $this->activitypub_plugin_version, EVENT_BRIDGE_FOR_ACTIVITYPUB_ACTIVITYPUB_PLUGIN_MIN_VERSION ) ) {
 			return;
 		}
 
+		// If the Event-Sources feature is enabled and all requirements are met, initialize it.
 		if ( ! is_user_type_disabled( 'blog' ) && get_option( 'event_bridge_for_activitypub_event_sources_active' ) ) {
 			Event_Sources::init();
 		}
+
+		// Lastly but most importantly: register the ActivityPub transformers for events to the ActivityPub plugin.
 		add_filter( 'activitypub_transformer', array( $this, 'register_activitypub_event_transformer' ), 10, 3 );
-		self::get_default_integration_class_name_used_for_event_sources_feature();
 	}
 
 	/**
diff --git a/includes/integrations/class-event-organiser.php b/includes/integrations/class-event-organiser.php
index d6c0348..55c03d4 100644
--- a/includes/integrations/class-event-organiser.php
+++ b/includes/integrations/class-event-organiser.php
@@ -2,7 +2,8 @@
 /**
  * Event Organiser.
  *
- * Defines all the necessary meta information for the Event Organiser plugin.
+ * Defines all the necessary meta information and methods for the integration
+ * of the WordPress "Event Organiser" plugin.
  *
  * @link    https://wordpress.org/plugins/event-organiser/
  * @package Event_Bridge_For_ActivityPub
@@ -17,9 +18,10 @@ use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event_Organiser as Even
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 /**
- * Interface for a supported event plugin.
+ * Event Organiser.
  *
- * This interface defines which information is necessary for a supported event plugin.
+ * Defines all the necessary meta information and methods for the integration
+ * of the WordPress "Event Organiser" plugin.
  *
  * @since 1.0.0
  */
diff --git a/includes/integrations/class-event-plugin-integration.php b/includes/integrations/class-event-plugin-integration.php
index 252bb64..d18d2ee 100644
--- a/includes/integrations/class-event-plugin-integration.php
+++ b/includes/integrations/class-event-plugin-integration.php
@@ -1,8 +1,8 @@
 <?php
 /**
- * Interface for defining supported Event Plugins.
+ * Abstract base class for a basic integration of a WordPress event plugin.
  *
- * Basic information that each supported event needs for this plugin to work.
+ * Basic information and methods that each supported event needs for this plugin to work.
  *
  * @package Event_Bridge_For_ActivityPub
  * @since 1.0.0
@@ -11,7 +11,7 @@
 
 namespace Event_Bridge_For_ActivityPub\Integrations;
 
-use Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event as ActivityPub_Event_Transformer;
+use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event as ActivityPub_Event_Transformer;
 
 // Exit if accessed directly.
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
@@ -19,9 +19,9 @@ defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 require_once EVENT_BRIDGE_FOR_ACTIVITYPUB_PLUGIN_DIR . 'includes/integrations/interface-feature-event-sources.php';
 
 /**
- * Interface for a supported event plugin.
+ * Abstract base class for a basic integration of a WordPress event plugin.
  *
- * This interface defines which information is necessary for a supported event plugin.
+ * Basic information and methods that each supported event needs for this plugin to work.
  *
  * @since 1.0.0
  */
diff --git a/includes/integrations/class-eventin.php b/includes/integrations/class-eventin.php
index 9cdb90c..d7ee1c2 100644
--- a/includes/integrations/class-eventin.php
+++ b/includes/integrations/class-eventin.php
@@ -1,10 +1,11 @@
 <?php
 /**
- * The Events Calendar.
+ * Eventin.
  *
- * Defines all the necessary meta information for the events calendar.
+ * Defines all the necessary meta information and methods for the integration of the
+ * WordPress plugin "Eventin".
  *
- * @link    https://wordpress.org/plugins/the-events-calendar/
+ * @link    https://wordpress.org/plugins/eventin/
  * @package Event_Bridge_For_ActivityPub
  * @since   1.0.0
  */
@@ -17,9 +18,10 @@ use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Eventin as Eventin_Tran
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 /**
- * Interface for a supported event plugin.
+ * Eventin.
  *
- * This interface defines which information is necessary for a supported event plugin.
+ * Defines all the necessary meta information and methods for the integration of the
+ * WordPress plugin "Eventin".
  *
  * @since 1.0.0
  */
diff --git a/includes/integrations/class-eventprime.php b/includes/integrations/class-eventprime.php
index abab86d..9c40849 100644
--- a/includes/integrations/class-eventprime.php
+++ b/includes/integrations/class-eventprime.php
@@ -1,6 +1,9 @@
 <?php
 /**
- * EventPrime – Events Calendar, Bookings and Tickets
+ * EventPrime – Events Calendar, Bookings and Tickets.
+ *
+ * Defines all the necessary meta information and methods for the integration of the
+ * WordPress plugin "EventPrime – Events Calendar, Bookings and Tickets".
  *
  * @link    https://wordpress.org/plugins/eventprime-event-calendar-management/
  * @package Event_Bridge_For_ActivityPub
@@ -18,7 +21,10 @@ use Eventprime_Basic_Functions;
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 /**
- * This class defines which information is necessary for the EventPrime event plugin.
+ * EventPrime – Events Calendar, Bookings and Tickets.
+ *
+ * Defines all the necessary meta information and methods for the integration of the
+ * WordPress plugin "EventPrime – Events Calendar, Bookings and Tickets".
  *
  * @since 1.0.0
  */
diff --git a/includes/integrations/class-events-manager.php b/includes/integrations/class-events-manager.php
index 099a4f7..4a43bec 100644
--- a/includes/integrations/class-events-manager.php
+++ b/includes/integrations/class-events-manager.php
@@ -2,7 +2,8 @@
 /**
  * Events Manager.
  *
- * Defines all the necessary meta information for the Events Manager WordPress Plugin.
+ * Defines all the necessary meta information and methods for the integration of the
+ * WordPress plugin "Events Manager".
  *
  * @link    https://wordpress.org/plugins/events-manager/
  * @package Event_Bridge_For_ActivityPub
@@ -17,9 +18,10 @@ use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Events_Manager as Event
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 /**
- * Interface for a supported event plugin.
+ * Events Manager.
  *
- * This interface defines which information is necessary for a supported event plugin.
+ * Defines all the necessary meta information and methods for the integration of the
+ * WordPress plugin "Events Manager".
  *
  * @since 1.0.0
  */
diff --git a/includes/integrations/class-gatherpress.php b/includes/integrations/class-gatherpress.php
index 1f446cc..c54156d 100644
--- a/includes/integrations/class-gatherpress.php
+++ b/includes/integrations/class-gatherpress.php
@@ -2,7 +2,8 @@
 /**
  * GatherPress.
  *
- * Defines all the necessary meta information for the GatherPress plugin.
+ * Defines all the necessary meta information and methods for the integration
+ * of the WordPress event plugin "GatherPress".
  *
  * @link    https://wordpress.org/plugins/gatherpress/
  * @package Event_Bridge_For_ActivityPub
@@ -18,9 +19,10 @@ use Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier\GatherPress as Gathe
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 /**
- * Interface for a supported event plugin.
+ * GatherPress.
  *
- * This interface defines which information is necessary for a supported event plugin.
+ * Defines all the necessary meta information and methods for the integration
+ * of the WordPress event plugin "GatherPress".
  *
  * @since 1.0.0
  */
diff --git a/includes/integrations/class-modern-events-calendar-lite.php b/includes/integrations/class-modern-events-calendar-lite.php
index 6abbd75..687476c 100644
--- a/includes/integrations/class-modern-events-calendar-lite.php
+++ b/includes/integrations/class-modern-events-calendar-lite.php
@@ -2,7 +2,8 @@
 /**
  * Modern Events Calendar (Lite)
  *
- * Defines all the necessary meta information for the Modern Events Calendar (Lite).
+ * Defines all the necessary meta information for the integration of the
+ * WordPress plugin "Modern Events Calendar (Lite)".
  *
  * @link    https://webnus.net/modern-events-calendar/
  * @package Event_Bridge_For_ActivityPub
@@ -17,9 +18,10 @@ use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Modern_Events_Calendar_
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 /**
- * Interface for a supported event plugin.
+ * Modern Events Calendar (Lite)
  *
- * This interface defines which information is necessary for a supported event plugin.
+ * Defines all the necessary meta information for the integration of the
+ * WordPress plugin "Modern Events Calendar (Lite)".
  *
  * @since 1.0.0
  */
diff --git a/includes/integrations/class-the-events-calendar.php b/includes/integrations/class-the-events-calendar.php
index 141d3fa..d3337fe 100644
--- a/includes/integrations/class-the-events-calendar.php
+++ b/includes/integrations/class-the-events-calendar.php
@@ -2,7 +2,8 @@
 /**
  * The Events Calendar.
  *
- * Defines all the necessary meta information for the events calendar.
+ * Defines all the necessary meta information for the integration of the
+ * WordPress plugin "The Events Calendar".
  *
  * @link    https://wordpress.org/plugins/the-events-calendar/
  * @package Event_Bridge_For_ActivityPub
@@ -18,9 +19,10 @@ use Event_Bridge_For_ActivityPub\ActivityPub\Transmogrifier\The_Events_Calendar
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 /**
- * Interface for a supported event plugin.
+ * The Events Calendar.
  *
- * This interface defines which information is necessary for a supported event plugin.
+ * Defines all the necessary meta information for the integration of the
+ * WordPress plugin "The Events Calendar".
  *
  * @since 1.0.0
  */
diff --git a/includes/integrations/class-vs-event-list.php b/includes/integrations/class-vs-event-list.php
index 17715d8..beb56b4 100644
--- a/includes/integrations/class-vs-event-list.php
+++ b/includes/integrations/class-vs-event-list.php
@@ -2,7 +2,7 @@
 /**
  * VS Events LIst.
  *
- * Defines all the necessary meta information for the WordPress event plugin
+ * Defines all the necessary meta information for the integration of the WordPress event plugin
  * "Very Simple Events List".
  *
  * @link    https://de.wordpress.org/plugins/very-simple-event-list/
@@ -18,9 +18,10 @@ use Event_Bridge_For_ActivityPub\ActivityPub\Transformer\VS_Event_List as VS_Eve
 defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
 
 /**
- * Interface for a supported event plugin.
+ * VS Events LIst.
  *
- * This interface defines which information is necessary for a supported event plugin.
+ * Defines all the necessary meta information for the integration of the WordPress event plugin
+ * "Very Simple Events List".
  *
  * @since 1.0.0
  */
diff --git a/includes/integrations/class-wp-event-manager.php b/includes/integrations/class-wp-event-manager.php
index 7e7c3e3..c879fe2 100644
--- a/includes/integrations/class-wp-event-manager.php
+++ b/includes/integrations/class-wp-event-manager.php
@@ -2,8 +2,8 @@
 /**
  * WP Event Manager.
  *
- * Defines all the necessary meta information for the WordPress event plugin
- * "WP Event Manager"
+ * Defines all the necessary meta information for the Integration of the
+ * WordPress event plugin "WP Event Manager".
  *
  * @link    https://de.wordpress.org/plugins/wp-event-manager
  * @package Event_Bridge_For_ActivityPub
diff --git a/includes/integrations/interface-feature-event-sources.php b/includes/integrations/interface-feature-event-sources.php
index b80f97d..4b43322 100644
--- a/includes/integrations/interface-feature-event-sources.php
+++ b/includes/integrations/interface-feature-event-sources.php
@@ -1,8 +1,10 @@
 <?php
 /**
- * Interface for defining supported Event Plugins.
+ * Interface for defining Methods needed for the Event Sources feature.
  *
- * Basic information that each supported event needs for this plugin to work.
+ * The Event Sources feature is about following other ActivityPub actors and
+ * importing their events. That means treating them as cache and listing them.
+ * Events should be deleted some time after they have ended.
  *
  * @package Event_Bridge_For_ActivityPub
  * @since 1.0.0
diff --git a/includes/table/class-event-sources.php b/includes/table/class-event-sources.php
index e8ecef5..533c25e 100644
--- a/includes/table/class-event-sources.php
+++ b/includes/table/class-event-sources.php
@@ -2,6 +2,9 @@
 /**
  * Event Sources Table-Class file.
  *
+ * This table display the event sources (=followed ActivityPub actors) that are used for
+ * importing (caching and displaying) remote events to the WordPress site.
+ *
  * @package Event_Bridge_For_ActivityPub
  * @since 1.0.0
  * @license AGPL-3.0-or-later
diff --git a/templates/welcome.php b/templates/welcome.php
index 2dc3977..0a557b1 100644
--- a/templates/welcome.php
+++ b/templates/welcome.php
@@ -1,6 +1,6 @@
 <?php
 /**
- * Status page for the Event Bridge for ActivityPub.
+ * Status/Welcome page for the Event Bridge for ActivityPub admin interface.
  *
  * @package Event_Bridge_For_ActivityPub
  * @since   1.0.0
diff --git a/tests/test-class-activitypub-event-bridge-shortcodes.php b/tests/test-class-activitypub-event-bridge-shortcodes.php
index 1256665..73f4768 100644
--- a/tests/test-class-activitypub-event-bridge-shortcodes.php
+++ b/tests/test-class-activitypub-event-bridge-shortcodes.php
@@ -44,7 +44,7 @@ class Test_Activitypub_Event_Bridge_Shortcodes extends WP_UnitTestCase {
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
-		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event ) {
 			return;
 		}
 
@@ -77,7 +77,7 @@ class Test_Activitypub_Event_Bridge_Shortcodes extends WP_UnitTestCase {
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
-		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event ) {
 			return;
 		}
 
@@ -110,7 +110,7 @@ class Test_Activitypub_Event_Bridge_Shortcodes extends WP_UnitTestCase {
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
-		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event ) {
 			return;
 		}
 
@@ -138,7 +138,7 @@ class Test_Activitypub_Event_Bridge_Shortcodes extends WP_UnitTestCase {
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
-		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event ) {
 			return;
 		}
 
@@ -174,7 +174,7 @@ class Test_Activitypub_Event_Bridge_Shortcodes extends WP_UnitTestCase {
 		// Call the transformer Factory.
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
-		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event ) {
+		if ( ! $transformer instanceof \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event ) {
 			return;
 		}
 
diff --git a/tests/test-class-plugin-event-organiser.php b/tests/test-class-plugin-event-organiser.php
index bd44949..6a3c521 100644
--- a/tests/test-class-plugin-event-organiser.php
+++ b/tests/test-class-plugin-event-organiser.php
@@ -62,7 +62,7 @@ class Test_Event_Organiser extends WP_UnitTestCase {
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( get_post( $post_id ) );
 
 		// Check that we got the right transformer.
-		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Event_Organiser::class, $transformer );
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Event_Organiser::class, $transformer );
 	}
 
 	/**
diff --git a/tests/test-class-plugin-eventin.php b/tests/test-class-plugin-eventin.php
index 51ec62a..d316f2b 100644
--- a/tests/test-class-plugin-eventin.php
+++ b/tests/test-class-plugin-eventin.php
@@ -64,7 +64,7 @@ class Test_Eventin extends WP_UnitTestCase {
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( get_post( $event->id ) );
 
 		// Check that we got the right transformer.
-		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Eventin::class, $transformer );
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Eventin::class, $transformer );
 	}
 
 	/**
diff --git a/tests/test-class-plugin-eventprime.php b/tests/test-class-plugin-eventprime.php
index e8c8ce3..1e750ff 100644
--- a/tests/test-class-plugin-eventprime.php
+++ b/tests/test-class-plugin-eventprime.php
@@ -93,7 +93,7 @@ class Test_EventPrime extends WP_UnitTestCase {
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
 		// Check that we got the right transformer.
-		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\EventPrime::class, $transformer );
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\EventPrime::class, $transformer );
 	}
 
 	/**
diff --git a/tests/test-class-plugin-events-manger.php b/tests/test-class-plugin-events-manger.php
index ae87919..956a332 100644
--- a/tests/test-class-plugin-events-manger.php
+++ b/tests/test-class-plugin-events-manger.php
@@ -61,7 +61,7 @@ class Test_Events_Manager extends WP_UnitTestCase {
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
 		// Check that we got the right transformer.
-		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Events_Manager::class, $transformer );
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Events_Manager::class, $transformer );
 	}
 
 	/**
diff --git a/tests/test-class-plugin-gatherpress.php b/tests/test-class-plugin-gatherpress.php
index 9a7a076..2fae248 100644
--- a/tests/test-class-plugin-gatherpress.php
+++ b/tests/test-class-plugin-gatherpress.php
@@ -65,7 +65,7 @@ class Test_GatherPress extends WP_UnitTestCase {
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $event->event );
 
 		// Check that we got the right transformer.
-		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\GatherPress::class, $transformer );
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\GatherPress::class, $transformer );
 	}
 
 	/**
diff --git a/tests/test-class-plugin-modern-events-calendar-lite.php b/tests/test-class-plugin-modern-events-calendar-lite.php
index 16db755..3e84a81 100644
--- a/tests/test-class-plugin-modern-events-calendar-lite.php
+++ b/tests/test-class-plugin-modern-events-calendar-lite.php
@@ -74,7 +74,7 @@ class Test_Modern_Events_Calendar_Lite extends WP_UnitTestCase {
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
 		// Check that we got the right transformer.
-		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\Modern_Events_Calendar_Lite::class, $transformer );
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\Modern_Events_Calendar_Lite::class, $transformer );
 	}
 
 	/**
diff --git a/tests/test-class-plugin-the-events-calendar.php b/tests/test-class-plugin-the-events-calendar.php
index b2ef602..c88bef7 100644
--- a/tests/test-class-plugin-the-events-calendar.php
+++ b/tests/test-class-plugin-the-events-calendar.php
@@ -91,7 +91,7 @@ class Test_The_Events_Calendar extends WP_UnitTestCase {
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
 		// Check that we got the right transformer.
-		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\The_Events_Calendar::class, $transformer );
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\The_Events_Calendar::class, $transformer );
 	}
 
 	/**
diff --git a/tests/test-class-plugin-vs-event-list.php b/tests/test-class-plugin-vs-event-list.php
index 96ce9e0..a99d43f 100644
--- a/tests/test-class-plugin-vs-event-list.php
+++ b/tests/test-class-plugin-vs-event-list.php
@@ -58,7 +58,7 @@ class Test_VS_Event_List extends WP_UnitTestCase {
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
 		// Check that we got the right transformer.
-		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\VS_Event_List::class, $transformer );
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\VS_Event_List::class, $transformer );
 	}
 
 	/**
diff --git a/tests/test-class-plugin-wp-event-manager.php b/tests/test-class-plugin-wp-event-manager.php
index cfc5191..af68b20 100644
--- a/tests/test-class-plugin-wp-event-manager.php
+++ b/tests/test-class-plugin-wp-event-manager.php
@@ -58,7 +58,7 @@ class Test_WP_Event_Manager extends WP_UnitTestCase {
 		$transformer = \Activitypub\Transformer\Factory::get_transformer( $wp_object );
 
 		// Check that we got the right transformer.
-		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\Activitypub\Transformer\WP_Event_Manager::class, $transformer );
+		$this->assertInstanceOf( \Event_Bridge_For_ActivityPub\ActivityPub\Transformer\WP_Event_Manager::class, $transformer );
 	}
 
 	/**