diff --git a/src/wp-admin/includes/class-wp-upgrader.php b/src/wp-admin/includes/class-wp-upgrader.php
index e2282ebd61..7f8ddc19c0 100644
--- a/src/wp-admin/includes/class-wp-upgrader.php
+++ b/src/wp-admin/includes/class-wp-upgrader.php
@@ -1832,7 +1832,7 @@ class Language_Pack_Upgrader extends WP_Upgrader {
 	 * @param string|false $update Optional. Whether an update offer is available. Default false.
 	 * @param array        $args   Optional. Other optional arguments, see
 	 *                             {@see Language_Pack_Upgrader::bulk_upgrade()}. Default empty array.
-	 * @return array|WP_Error The result of the upgrade, or a {@see wP_Error} object instead.
+	 * @return array|bool|WP_Error The result of the upgrade, or a {@see wP_Error} object instead.
 	 */
 	public function upgrade( $update = false, $args = array() ) {
 		if ( $update ) {
@@ -1862,7 +1862,7 @@ class Language_Pack_Upgrader extends WP_Upgrader {
 	 *     @type bool $clear_update_cache Whether to clear the update cache when done.
 	 *                                    Default true.
 	 * }
-	 * @return array|true|false|WP_Error Will return an array of results, or true if there are no updates,
+	 * @return array|bool|WP_Error Will return an array of results, or true if there are no updates,
 	 *                                   false or WP_Error for initial errors.
 	 */
 	public function bulk_upgrade( $language_updates = array(), $args = array() ) {
diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index 728bb1af61..1dce3aa161 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -4608,7 +4608,7 @@ function _get_non_cached_ids( $object_ids, $cache_key ) {
  * @since 3.4.0
  * @access private
  *
- * @return bool true|false Whether the device is able to upload files.
+ * @return bool Whether the device is able to upload files.
  */
 function _device_can_upload() {
 	if ( ! wp_is_mobile() )
diff --git a/src/wp-includes/vars.php b/src/wp-includes/vars.php
index d58dc4bae6..828fbbb4ab 100644
--- a/src/wp-includes/vars.php
+++ b/src/wp-includes/vars.php
@@ -120,7 +120,7 @@ $is_iis7 = $is_IIS && intval( substr( $_SERVER['SERVER_SOFTWARE'], strpos( $_SER
  *
  * @staticvar bool $is_mobile
  *
- * @return bool true|false
+ * @return bool
  */
 function wp_is_mobile() {
 	static $is_mobile = null;