diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index b5327ed788..0050d10b7c 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -3172,8 +3172,9 @@ function wp_list_filter( $list, $args = array(), $operator = 'AND' ) {
  * @param int|string $field     Field from the object to place instead of the entire object
  * @param int|string $index_key Optional. Field from the object to use as keys for the new array.
  *                              Default null.
- * @return array Array of found values. If $index_key is set, an array of found values with keys
- *               corresponding to $index_key.
+ * @return array Array of found values. If `$index_key` is set, an array of found values with keys
+ *               corresponding to `$index_key`. If `$index_key` is null, array keys from the original
+ *               `$list` will be preserved in the results.
  */
 function wp_list_pluck( $list, $field, $index_key = null ) {
 	if ( ! $index_key ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index d48b34f2c0..4b55c00b9a 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31450';
+$wp_version = '4.2-alpha-31451';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.