diff --git a/wp-admin/includes/media.php b/wp-admin/includes/media.php
index 599bff8862..737a3fc5f0 100644
--- a/wp-admin/includes/media.php
+++ b/wp-admin/includes/media.php
@@ -247,14 +247,15 @@ win.send_to_editor('<?php echo addslashes($html); ?>');
 }
 
 /**
- * This handles the file upload POST itself, creating the attachment post.
+ * Save a file submitted from a POST request and create an attachment post for it.
  *
  * @since 2.5.0
  *
- * @param string $file_id Index into the {@link $_FILES} array of the upload
- * @param int $post_id The post ID the media is associated with
- * @param array $post_data allows you to overwrite some of the attachment
- * @param array $overrides allows you to override the {@link wp_handle_upload()} behavior
+ * @param string $file_id   Index of the {@link $_FILES} array that the file was sent. Required.
+ * @param int    $post_id   The post ID of a post to attach the media item to. Required, but can
+ *                          be set to 0, creating a media item that has no relationship to a post.
+ * @param array  $post_data Overwrite some of the attachment. Optional.
+ * @param array  $overrides Override the {@link wp_handle_upload()} behavior. Optional.
  * @return int|WP_Error ID of the attachment or a WP_Error object on failure.
  */
 function media_handle_upload($file_id, $post_id, $post_data = array(), $overrides = array( 'test_form' => false )) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 2795fb6075..9dc701b423 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31108';
+$wp_version = '4.2-alpha-31109';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.