diff --git a/composer.json b/composer.json
index 8d23204..7fc6fbe 100644
--- a/composer.json
+++ b/composer.json
@@ -22,6 +22,7 @@
     },
     "license": "GPL-2.0+",
     "require-dev": {
+        "drupal/jsonapi_extras": "~3.13",
         "drupal/search_api": "~1.0"
     }
 }
diff --git a/modules/entity_visibility_preview_simple_grants/src/Service/EntityVisibilityPreviewSimpleGrantsGrantsHelperInterface.php b/modules/entity_visibility_preview_simple_grants/src/Service/EntityVisibilityPreviewSimpleGrantsGrantsHelperInterface.php
index cdd2f31..ee22e9d 100644
--- a/modules/entity_visibility_preview_simple_grants/src/Service/EntityVisibilityPreviewSimpleGrantsGrantsHelperInterface.php
+++ b/modules/entity_visibility_preview_simple_grants/src/Service/EntityVisibilityPreviewSimpleGrantsGrantsHelperInterface.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\entity_visibility_preview_simple_grants\Service;
 
 use Drupal\Core\Session\AccountInterface;
diff --git a/src/Controller/PreviewMessage.php b/src/Controller/PreviewMessage.php
index c515d5d..cac3aa0 100644
--- a/src/Controller/PreviewMessage.php
+++ b/src/Controller/PreviewMessage.php
@@ -19,7 +19,7 @@ class PreviewMessage extends ControllerBase {
    *
    * @var \Drupal\entity_visibility_preview\EntityVisibilityPreviewConditionPluginManager
    */
-  public $entityVisibilityPreviewConditionPluginManager;
+  protected $entityVisibilityPreviewConditionPluginManager;
 
   /**
    * The renderer service.
diff --git a/src/Service/EntityVisibilityPreviewFieldHelper.php b/src/Service/EntityVisibilityPreviewFieldHelper.php
index 7c798c5..1f16ef7 100644
--- a/src/Service/EntityVisibilityPreviewFieldHelper.php
+++ b/src/Service/EntityVisibilityPreviewFieldHelper.php
@@ -93,7 +93,7 @@ class EntityVisibilityPreviewFieldHelper implements EntityVisibilityPreviewField
   }
 
   /**
-   * {@inheritDoc}
+   * {@inheritdoc}
    */
   public function getEntityVisibilityPreviewFieldsForBundle($entityType, $entityBundle) : array {
     $fields = $this->getAllEntityVisibilityPreviewFields();
diff --git a/src/Service/EntityVisibilityPreviewFieldHelperInterface.php b/src/Service/EntityVisibilityPreviewFieldHelperInterface.php
index aa44e7e..813db1b 100644
--- a/src/Service/EntityVisibilityPreviewFieldHelperInterface.php
+++ b/src/Service/EntityVisibilityPreviewFieldHelperInterface.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\entity_visibility_preview\Service;
 
 /**
@@ -41,10 +43,10 @@ interface EntityVisibilityPreviewFieldHelperInterface {
    * @param string $entityBundle
    *   The desired bundle.
    *
-   * @see $this->getAllEntityVisibilityPreviewFields()
-   *
    * @return array
    *   An array of fields.
+   *
+   * @see $this->getAllEntityVisibilityPreviewFields()
    */
   public function getEntityVisibilityPreviewFieldsForBundle($entityType, $entityBundle) : array;
 
diff --git a/src/Service/EntityVisibilityPreviewTaxonomyHelperInterface.php b/src/Service/EntityVisibilityPreviewTaxonomyHelperInterface.php
index e6d9284..2df304a 100644
--- a/src/Service/EntityVisibilityPreviewTaxonomyHelperInterface.php
+++ b/src/Service/EntityVisibilityPreviewTaxonomyHelperInterface.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types = 1);
+
 namespace Drupal\entity_visibility_preview\Service;
 
 /**