diff --git a/src/wp-includes/formatting.php b/src/wp-includes/formatting.php
index d25b69ebdb..89ecbbefa9 100644
--- a/src/wp-includes/formatting.php
+++ b/src/wp-includes/formatting.php
@@ -3888,7 +3888,7 @@ function sanitize_option( $option, $value ) {
  *
  * @param mixed    $value    The array, object, or scalar.
  * @param callable $callback The function to map onto $value.
- * @return The value with the callback applied to all non-arrays and non-objects inside it.
+ * @return mixed The value with the callback applied to all non-arrays and non-objects inside it.
  */
 function map_deep( $value, $callback ) {
 	if ( is_array( $value ) ) {