diff -r c7c34916027a -r 177826044cd9 wp/wp-includes/feed-rdf.php
--- a/wp/wp-includes/feed-rdf.php	Mon Oct 14 18:06:33 2019 +0200
+++ b/wp/wp-includes/feed-rdf.php	Mon Oct 14 18:28:13 2019 +0200
@@ -5,10 +5,10 @@
  * @package WordPress
  */
 
-header('Content-Type: ' . feed_content_type('rdf') . '; charset=' . get_option('blog_charset'), true);
+header( 'Content-Type: ' . feed_content_type( 'rdf' ) . '; charset=' . get_option( 'blog_charset' ), true );
 $more = 1;
 
-echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>';
+echo '<?xml version="1.0" encoding="' . get_option( 'blog_charset' ) . '"?' . '>';
 
 /** This action is documented in wp-includes/feed-rss2.php */
 do_action( 'rss_tag_pre', 'rdf' );
@@ -29,22 +29,23 @@
 	do_action( 'rdf_ns' );
 	?>
 >
-<channel rdf:about="<?php bloginfo_rss("url") ?>">
+<channel rdf:about="<?php bloginfo_rss( 'url' ); ?>">
 	<title><?php wp_title_rss(); ?></title>
-	<link><?php bloginfo_rss('url') ?></link>
-	<description><?php bloginfo_rss('description') ?></description>
-	<dc:date><?php
-		$date = get_lastpostmodified( 'GMT' );
-		echo $date ? mysql2date( 'Y-m-d\TH:i:s\Z', $date ) : date( 'Y-m-d\TH:i:s\Z' );
-	?></dc:date>
-	<sy:updatePeriod><?php
+	<link><?php bloginfo_rss( 'url' ); ?></link>
+	<description><?php bloginfo_rss( 'description' ); ?></description>
+	<dc:date><?php echo get_feed_build_date( 'Y-m-d\TH:i:s\Z' ); ?>	</dc:date>
+	<sy:updatePeriod>
+	<?php
 		/** This filter is documented in wp-includes/feed-rss2.php */
 		echo apply_filters( 'rss_update_period', 'hourly' );
-	?></sy:updatePeriod>
-	<sy:updateFrequency><?php
+	?>
+	</sy:updatePeriod>
+	<sy:updateFrequency>
+	<?php
 		/** This filter is documented in wp-includes/feed-rss2.php */
 		echo apply_filters( 'rss_update_frequency', '1' );
-	?></sy:updateFrequency>
+	?>
+	</sy:updateFrequency>
 	<sy:updateBase>2000-01-01T12:00+00:00</sy:updateBase>
 	<?php
 	/**
@@ -56,24 +57,31 @@
 	?>
 	<items>
 		<rdf:Seq>
-		<?php while (have_posts()): the_post(); ?>
-			<rdf:li rdf:resource="<?php the_permalink_rss() ?>"/>
+		<?php
+		while ( have_posts() ) :
+			the_post();
+			?>
+			<rdf:li rdf:resource="<?php the_permalink_rss(); ?>"/>
 		<?php endwhile; ?>
 		</rdf:Seq>
 	</items>
 </channel>
-<?php rewind_posts(); while (have_posts()): the_post(); ?>
-<item rdf:about="<?php the_permalink_rss() ?>">
-	<title><?php the_title_rss() ?></title>
-	<link><?php the_permalink_rss() ?></link>
-	<dc:date><?php echo mysql2date('Y-m-d\TH:i:s\Z', $post->post_date_gmt, false); ?></dc:date>
-	<dc:creator><![CDATA[<?php the_author() ?>]]></dc:creator>
-	<?php the_category_rss('rdf') ?>
-<?php if (get_option('rss_use_excerpt')) : ?>
-	<description><![CDATA[<?php the_excerpt_rss() ?>]]></description>
+<?php
+rewind_posts();
+while ( have_posts() ) :
+	the_post();
+	?>
+<item rdf:about="<?php the_permalink_rss(); ?>">
+	<title><?php the_title_rss(); ?></title>
+	<link><?php the_permalink_rss(); ?></link>
+	<dc:date><?php echo mysql2date( 'Y-m-d\TH:i:s\Z', $post->post_date_gmt, false ); ?></dc:date>
+	<dc:creator><![CDATA[<?php the_author(); ?>]]></dc:creator>
+	<?php the_category_rss( 'rdf' ); ?>
+	<?php if ( get_option( 'rss_use_excerpt' ) ) : ?>
+	<description><![CDATA[<?php the_excerpt_rss(); ?>]]></description>
 <?php else : ?>
-	<description><![CDATA[<?php the_excerpt_rss() ?>]]></description>
-	<content:encoded><![CDATA[<?php the_content_feed('rdf') ?>]]></content:encoded>
+	<description><![CDATA[<?php the_excerpt_rss(); ?>]]></description>
+	<content:encoded><![CDATA[<?php the_content_feed( 'rdf' ); ?>]]></content:encoded>
 <?php endif; ?>
 	<?php
 	/**
@@ -84,5 +92,5 @@
 	do_action( 'rdf_item' );
 	?>
 </item>
-<?php endwhile;  ?>
+<?php endwhile; ?>
 </rdf:RDF>