diff --git a/wp-includes/class-wp-customize-manager.php b/wp-includes/class-wp-customize-manager.php
index a00ebaf840..2653247aed 100644
--- a/wp-includes/class-wp-customize-manager.php
+++ b/wp-includes/class-wp-customize-manager.php
@@ -1855,7 +1855,11 @@ final class WP_Customize_Manager {
 
 		$this->add_control( new WP_Customize_Site_Icon_Control( $this, 'site_icon', array(
 			'label'       => __( 'Site Icon' ),
-			'description' => __( 'The Site Icon is used as a browser and app icon for your site. Icons must be square, and at least <strong>512</strong> pixels wide and tall.' ),
+			'description' => sprintf(
+				/* translators: %s: site icon size in pixels */
+				__( 'The Site Icon is used as a browser and app icon for your site. Icons must be square, and at least %s pixels wide and tall.' ),
+				'<strong>512</strong>'
+			),
 			'section'     => 'title_tagline',
 			'priority'    => 60,
 			'height'      => 512,
diff --git a/wp-includes/customize/class-wp-customize-header-image-control.php b/wp-includes/customize/class-wp-customize-header-image-control.php
index 52d52c18d5..8bbb572b8f 100644
--- a/wp-includes/customize/class-wp-customize-header-image-control.php
+++ b/wp-includes/customize/class-wp-customize-header-image-control.php
@@ -176,11 +176,20 @@ class WP_Customize_Header_Image_Control extends WP_Customize_Image_Control {
 			<p class="customizer-section-intro">
 				<?php
 				if ( $width && $height ) {
-					printf( __( 'While you can crop images to your liking after clicking <strong>Add new image</strong>, your theme recommends a header size of <strong>%s &times; %s</strong> pixels.' ), $width, $height );
+					/* translators: %s: header size in pixels */
+					printf( __( 'While you can crop images to your liking after clicking <strong>Add new image</strong>, your theme recommends a header size of %s pixels.' ),
+						sprintf( '<strong>%s &times; %s</strong>', $width, $height )
+					);
 				} elseif ( $width ) {
-					printf( __( 'While you can crop images to your liking after clicking <strong>Add new image</strong>, your theme recommends a header width of <strong>%s</strong> pixels.' ), $width );
+					/* translators: %s: header width in pixels */
+					printf( __( 'While you can crop images to your liking after clicking <strong>Add new image</strong>, your theme recommends a header width of %s pixels.' ),
+						sprintf( '<strong>%s</strong>', $width )
+					);
 				} else {
-					printf( __( 'While you can crop images to your liking after clicking <strong>Add new image</strong>, your theme recommends a header height of <strong>%s</strong> pixels.' ), $height );
+					/* translators: %s: header height in pixels */
+					printf( __( 'While you can crop images to your liking after clicking <strong>Add new image</strong>, your theme recommends a header height of %s pixels.' ),
+						sprintf( '<strong>%s</strong>', $height )
+					);
 				}
 				?>
 			</p>
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 27f849fa2b..d39c99c5df 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.5-alpha-35922';
+$wp_version = '4.5-alpha-35923';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.