diff --git a/src/wp-includes/post.php b/src/wp-includes/post.php
index 4ce2ac19e5..606d2669ab 100644
--- a/src/wp-includes/post.php
+++ b/src/wp-includes/post.php
@@ -2853,8 +2853,10 @@ function wp_untrash_post_comments( $post = null ) {
  *
  * @param int   $post_id Optional. The Post ID. Does not default to the ID of the
  *                       global $post. Default 0.
- * @param array $args    Optional. Category arguments. Default empty.
- * @return array List of categories.
+ * @param array $args    Optional. Category arguments. See wp_get_object_terms(). Default empty.
+ * @return array List of categories. If the `$fields` argument passed via `$args` is 'all' or
+ *               'all_with_object_id', an array of WP_Term objects will be returned. If `$fields`
+ *               is 'ids', an array of category ids. If `$fields` is 'names', an array of category names.
  */
 function wp_get_post_categories( $post_id = 0, $args = array() ) {
 	$post_id = (int) $post_id;