.../image/src/Plugin/DataType/ComputedImageStyleDerivatives.php     | 6 ++++--
 .../image/src/Plugin/DataType/ImageStyleDerivativesDefinition.php   | 5 ++++-
 .../media/tests/src/Functional/Rest/MediaResourceTestBase.php       | 1 -
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/core/modules/image/src/Plugin/DataType/ComputedImageStyleDerivatives.php b/core/modules/image/src/Plugin/DataType/ComputedImageStyleDerivatives.php
index b7de030..19d99e3 100644
--- a/core/modules/image/src/Plugin/DataType/ComputedImageStyleDerivatives.php
+++ b/core/modules/image/src/Plugin/DataType/ComputedImageStyleDerivatives.php
@@ -8,13 +8,15 @@
 use Drupal\image\ImageStyleInterface;
 
 /**
- * Computed map class for \Drupal\image\Plugin\DataType\ImageStyle.
+ * Computed image style derivatives class.
+ *
  * @ingroup typed_data
+ * @see \Drupal\image\Plugin\DataType\ImageStyle
  *
  * @DataType(
  *   id = "image_style_derivatives",
  *   label = @Translation("Image style derivatives"),
- *   definition_class = "\Drupal\image\Plugin\DataType\ImageStyleDerivativesDefinition"
+ *   definition_class = "\Drupal\image\Plugin\DataType\ImageStyleDerivativesDefinition",
  * )
  */
 class ComputedImageStyleDerivatives extends Map {
diff --git a/core/modules/image/src/Plugin/DataType/ImageStyleDerivativesDefinition.php b/core/modules/image/src/Plugin/DataType/ImageStyleDerivativesDefinition.php
index d1e609d..8978f2f 100644
--- a/core/modules/image/src/Plugin/DataType/ImageStyleDerivativesDefinition.php
+++ b/core/modules/image/src/Plugin/DataType/ImageStyleDerivativesDefinition.php
@@ -7,7 +7,10 @@
 use Drupal\image\Entity\ImageStyle;
 
 /**
- * @todo
+ * The definition of image style list, containing "width", "height" and "url".
+ *
+ * @see \Drupal\image\Plugin\DataType\ComputedImageStyleDerivatives
+ * @see \Drupal\image\Plugin\Field\FieldType\ImageItem::propertyDefinitions()
  */
 class ImageStyleDerivativesDefinition extends MapDataDefinition {
 
diff --git a/core/modules/media/tests/src/Functional/Rest/MediaResourceTestBase.php b/core/modules/media/tests/src/Functional/Rest/MediaResourceTestBase.php
index ae16e2c..456351e 100644
--- a/core/modules/media/tests/src/Functional/Rest/MediaResourceTestBase.php
+++ b/core/modules/media/tests/src/Functional/Rest/MediaResourceTestBase.php
@@ -5,7 +5,6 @@
 use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Url;
 use Drupal\file\Entity\File;
-use Drupal\image\Entity\ImageStyle;
 use Drupal\media\Entity\Media;
 use Drupal\media\Entity\MediaType;
 use Drupal\rest\RestResourceConfigInterface;