diff --git a/wp-includes/class-wp-customize-control.php b/wp-includes/class-wp-customize-control.php
index 9cba28c06c..e8004dd4e4 100644
--- a/wp-includes/class-wp-customize-control.php
+++ b/wp-includes/class-wp-customize-control.php
@@ -215,7 +215,7 @@ class WP_Customize_Control {
 	 * @since 4.0.0
 	 * @access public
 	 *
-	 * @return bool Always true.
+	 * @return true Always true.
 	 */
 	public function active_callback() {
 		return true;
@@ -679,6 +679,8 @@ class WP_Customize_Media_Control extends WP_Customize_Control {
 	 * @since 4.2.0 Moved from WP_Customize_Upload_Control.
 	 *
 	 * @param WP_Customize_Manager $manager {@see WP_Customize_Manager} instance.
+	 * @param string $id
+	 * @param array $args
 	 */
 	public function __construct( $manager, $id, $args = array() ) {
 		parent::__construct( $manager, $id, $args );
@@ -1123,13 +1125,15 @@ class WP_Customize_Header_Image_Control extends WP_Customize_Image_Control {
 		<?php
 	}
 
+	/**
+	 * @return string|null
+	 */
 	public function get_current_image_src() {
 		$src = $this->value();
 		if ( isset( $this->get_url ) ) {
 			$src = call_user_func( $this->get_url, $src );
 			return $src;
 		}
-		return null;
 	}
 
 	public function render_content() {
diff --git a/wp-includes/class-wp-customize-manager.php b/wp-includes/class-wp-customize-manager.php
index 8d78bddaef..0c6da25423 100644
--- a/wp-includes/class-wp-customize-manager.php
+++ b/wp-includes/class-wp-customize-manager.php
@@ -647,6 +647,8 @@ final class WP_Customize_Manager {
 	 * Removes the signature in case we experience a case where the Customizer was not properly executed.
 	 *
 	 * @since 3.4.0
+	 *
+	 * @return mixed
 	 */
 	public function remove_preview_signature( $return = null ) {
 		remove_action( 'shutdown', array( $this, 'customize_preview_signature' ), 1000 );
@@ -841,7 +843,7 @@ final class WP_Customize_Manager {
 	 *
 	 * @since 4.2.0
 	 *
-	 * @param string $setting_ids The setting IDs to add.
+	 * @param array $setting_ids The setting IDs to add.
 	 * @return WP_Customize_Setting The settings added.
 	 */
 	public function add_dynamic_settings( $setting_ids ) {
@@ -897,7 +899,7 @@ final class WP_Customize_Manager {
 	 * @since 3.4.0
 	 *
 	 * @param string $id Customize Setting ID.
-	 * @return WP_Customize_Setting
+	 * @return WP_Customize_Setting|null The setting, if set.
 	 */
 	public function get_setting( $id ) {
 		if ( isset( $this->settings[ $id ] ) ) {
@@ -942,7 +944,7 @@ final class WP_Customize_Manager {
 	 * @access public
 	 *
 	 * @param string $id Panel ID to get.
-	 * @return WP_Customize_Panel Requested panel instance.
+	 * @return WP_Customize_Panel|null Requested panel instance, if set.
 	 */
 	public function get_panel( $id ) {
 		if ( isset( $this->panels[ $id ] ) ) {
@@ -985,7 +987,7 @@ final class WP_Customize_Manager {
 	 * @since 3.4.0
 	 *
 	 * @param string $id Section ID.
-	 * @return WP_Customize_Section
+	 * @return WP_Customize_Section|null The section, if set.
 	 */
 	public function get_section( $id ) {
 		if ( isset( $this->sections[ $id ] ) )
@@ -1027,7 +1029,7 @@ final class WP_Customize_Manager {
 	 * @since 3.4.0
 	 *
 	 * @param string $id ID of the control.
-	 * @return WP_Customize_Control $control The control object.
+	 * @return WP_Customize_Control|null The control object, if set.
 	 */
 	public function get_control( $id ) {
 		if ( isset( $this->controls[ $id ] ) )
@@ -1513,7 +1515,7 @@ final class WP_Customize_Manager {
 	 * @since 3.4.0
 	 *
 	 * @param string $color
-	 * @return string
+	 * @return mixed
 	 */
 	public function _sanitize_header_textcolor( $color ) {
 		if ( 'blank' === $color )
@@ -1545,8 +1547,6 @@ function sanitize_hex_color( $color ) {
 	// 3 or 6 hex digits, or the empty string.
 	if ( preg_match('|^#([A-Fa-f0-9]{3}){1,2}$|', $color ) )
 		return $color;
-
-	return null;
 }
 
 /**
diff --git a/wp-includes/class-wp-customize-section.php b/wp-includes/class-wp-customize-section.php
index b852dfbacd..a27f22b0c1 100644
--- a/wp-includes/class-wp-customize-section.php
+++ b/wp-includes/class-wp-customize-section.php
@@ -207,7 +207,7 @@ class WP_Customize_Section {
 	 * @since 4.1.0
 	 * @access public
 	 *
-	 * @return bool Always true.
+	 * @return true Always true.
 	 */
 	public function active_callback() {
 		return true;
diff --git a/wp-includes/class-wp-customize-setting.php b/wp-includes/class-wp-customize-setting.php
index f8f9ce083b..ad555ba132 100644
--- a/wp-includes/class-wp-customize-setting.php
+++ b/wp-includes/class-wp-customize-setting.php
@@ -133,7 +133,7 @@ class WP_Customize_Setting {
 	 */
 	public function is_current_blog_previewed() {
 		if ( ! isset( $this->_previewed_blog_id ) ) {
-			return null;
+			return;
 		}
 		return ( get_current_blog_id() === $this->_previewed_blog_id );
 	}
@@ -275,8 +275,8 @@ class WP_Customize_Setting {
 	 *
 	 * @since 3.4.0
 	 *
-	 * @param mixed $value The value to sanitize.
-	 * @return mixed Null if an input isn't valid, otherwise the sanitized value.
+	 * @param string|array $value The value to sanitize.
+	 * @return string|array|null Null if an input isn't valid, otherwise the sanitized value.
 	 */
 	public function sanitize( $value ) {
 		$value = wp_unslash( $value );
@@ -331,18 +331,19 @@ class WP_Customize_Setting {
 	 * @since 3.4.0
 	 *
 	 * @param mixed $value The value to update.
-	 * @return mixed The result of saving the value.
 	 */
 	protected function _update_theme_mod( $value ) {
 		// Handle non-array theme mod.
-		if ( empty( $this->id_data[ 'keys' ] ) )
-			return set_theme_mod( $this->id_data[ 'base' ], $value );
-
+		if ( empty( $this->id_data[ 'keys' ] ) ) {
+			set_theme_mod( $this->id_data[ 'base' ], $value );
+			return;
+		}
 		// Handle array-based theme mod.
 		$mods = get_theme_mod( $this->id_data[ 'base' ] );
 		$mods = $this->multidimensional_replace( $mods, $this->id_data[ 'keys' ], $value );
-		if ( isset( $mods ) )
-			return set_theme_mod( $this->id_data[ 'base' ], $mods );
+		if ( isset( $mods ) ) {
+			set_theme_mod( $this->id_data[ 'base' ], $mods );
+		}
 	}
 
 	/**
@@ -351,7 +352,7 @@ class WP_Customize_Setting {
 	 * @since 3.4.0
 	 *
 	 * @param mixed $value The value to update.
-	 * @return bool|null The result of saving the value.
+	 * @return bool The result of saving the value.
 	 */
 	protected function _update_option( $value ) {
 		// Handle non-array option.
diff --git a/wp-includes/class-wp-customize-widgets.php b/wp-includes/class-wp-customize-widgets.php
index 1a87581ebe..a9f67add0c 100644
--- a/wp-includes/class-wp-customize-widgets.php
+++ b/wp-includes/class-wp-customize-widgets.php
@@ -122,7 +122,6 @@ final class WP_Customize_Widgets {
 				return $type;
 			}
 		}
-		return null;
 	}
 
 	/**
@@ -236,6 +235,7 @@ final class WP_Customize_Widgets {
 	 * @access public
 	 *
 	 * @param array $old_sidebars_widgets
+	 * @return array
 	 */
 	public function filter_customize_value_old_sidebars_widgets_data( $old_sidebars_widgets ) {
 		return $this->old_sidebars_widgets;
@@ -253,6 +253,7 @@ final class WP_Customize_Widgets {
 	 * @access public
 	 *
 	 * @param array $sidebars_widgets
+	 * @return array
 	 */
 	public function filter_option_sidebars_widgets_for_theme_switch( $sidebars_widgets ) {
 		$sidebars_widgets = $GLOBALS['sidebars_widgets'];
@@ -918,6 +919,7 @@ final class WP_Customize_Widgets {
 	 * @access public
 	 *
 	 * @param array $sidebars_widgets List of widgets for the current sidebar.
+	 * @return array
 	 */
 	public function preview_sidebars_widgets( $sidebars_widgets ) {
 		$sidebars_widgets = get_option( 'sidebars_widgets' );
@@ -1040,6 +1042,7 @@ final class WP_Customize_Widgets {
 	 *
 	 * @param bool   $is_active  Whether the sidebar is active.
 	 * @param string $sidebar_id Sidebar ID.
+	 * @return bool
 	 */
 	public function tally_sidebars_via_is_active_sidebar_calls( $is_active, $sidebar_id ) {
 		if ( isset( $GLOBALS['wp_registered_sidebars'][$sidebar_id] ) ) {
@@ -1065,6 +1068,7 @@ final class WP_Customize_Widgets {
 	 *
 	 * @param bool   $has_widgets Whether the current sidebar has widgets.
 	 * @param string $sidebar_id  Sidebar ID.
+	 * @return bool
 	 */
 	public function tally_sidebars_via_dynamic_sidebar_calls( $has_widgets, $sidebar_id ) {
 		if ( isset( $GLOBALS['wp_registered_sidebars'][$sidebar_id] ) ) {
@@ -1105,7 +1109,7 @@ final class WP_Customize_Widgets {
 	 * @access public
 	 *
 	 * @param array $value Widget instance to sanitize.
-	 * @return array Sanitized widget instance.
+	 * @return array|null Sanitized widget instance.
 	 */
 	public function sanitize_widget_instance( $value ) {
 		if ( $value === array() ) {
@@ -1116,21 +1120,21 @@ final class WP_Customize_Widgets {
 			|| empty( $value['instance_hash_key'] )
 			|| empty( $value['encoded_serialized_instance'] ) )
 		{
-			return null;
+			return;
 		}
 
 		$decoded = base64_decode( $value['encoded_serialized_instance'], true );
 		if ( false === $decoded ) {
-			return null;
+			return;
 		}
 
 		if ( $this->get_instance_hash_key( $decoded ) !== $value['instance_hash_key'] ) {
-			return null;
+			return;
 		}
 
 		$instance = unserialize( $decoded );
 		if ( false === $instance ) {
-			return null;
+			return;
 		}
 
 		return $instance;
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 2a5bc0b35e..c17bca96d9 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.3-alpha-32534';
+$wp_version = '4.3-alpha-32535';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.