diff --git a/src/wp-includes/post.php b/src/wp-includes/post.php
index e196d09726..1ab5ab1501 100644
--- a/src/wp-includes/post.php
+++ b/src/wp-includes/post.php
@@ -5898,13 +5898,22 @@ function wp_delete_attachment_files( $post_id, $meta, $backup_sizes, $file ) {
 }
 
 /**
- * Retrieve attachment meta field for attachment ID.
+ * Retrieves attachment metadata for attachment ID.
  *
  * @since 2.1.0
  *
  * @param int  $attachment_id Attachment post ID. Defaults to global $post.
  * @param bool $unfiltered    Optional. If true, filters are not run. Default false.
- * @return mixed Attachment meta field. False on failure.
+ * @return array|false {
+ *     Attachment metadata. False on failure.
+ *
+ *     @type int    $width      The width of the attachment.
+ *     @type int    $height     The height of the attachment.
+ *     @type string $file       The file path relative to `wp-content/uploads`.
+ *     @type array  $sizes      Keys are size slugs, each value is an array containing
+ *                              'file', 'width', 'height', and 'mime-type'.
+ *     @type array  $image_meta Image metadata.
+ * }
  */
 function wp_get_attachment_metadata( $attachment_id = 0, $unfiltered = false ) {
 	$attachment_id = (int) $attachment_id;
@@ -5933,7 +5942,7 @@ function wp_get_attachment_metadata( $attachment_id = 0, $unfiltered = false ) {
 }
 
 /**
- * Update metadata for an attachment.
+ * Updates metadata for an attachment.
  *
  * @since 2.1.0
  *