diff -r 3d4e9c994f10 -r a86126ab1dd4 wp/wp-includes/widgets/class-wp-widget-rss.php
--- a/wp/wp-includes/widgets/class-wp-widget-rss.php	Tue Oct 22 16:11:46 2019 +0200
+++ b/wp/wp-includes/widgets/class-wp-widget-rss.php	Tue Dec 15 13:49:49 2020 +0100
@@ -48,7 +48,7 @@
 		}
 
 		$url = ! empty( $instance['url'] ) ? $instance['url'] : '';
-		while ( stristr( $url, 'http' ) != $url ) {
+		while ( stristr( $url, 'http' ) !== $url ) {
 			$url = substr( $url, 1 );
 		}
 
@@ -56,8 +56,8 @@
 			return;
 		}
 
-		// self-url destruction sequence
-		if ( in_array( untrailingslashit( $url ), array( site_url(), home_url() ) ) ) {
+		// Self-URL destruction sequence.
+		if ( in_array( untrailingslashit( $url ), array( site_url(), home_url() ), true ) ) {
 			return;
 		}
 
@@ -67,12 +67,12 @@
 		$link  = '';
 
 		if ( ! is_wp_error( $rss ) ) {
-			$desc = esc_attr( strip_tags( @html_entity_decode( $rss->get_description(), ENT_QUOTES, get_option( 'blog_charset' ) ) ) );
+			$desc = esc_attr( strip_tags( html_entity_decode( $rss->get_description(), ENT_QUOTES, get_option( 'blog_charset' ) ) ) );
 			if ( empty( $title ) ) {
 				$title = strip_tags( $rss->get_title() );
 			}
 			$link = strip_tags( $rss->get_permalink() );
-			while ( stristr( $link, 'http' ) != $link ) {
+			while ( stristr( $link, 'http' ) !== $link ) {
 				$link = substr( $link, 1 );
 			}
 		}
@@ -94,7 +94,25 @@
 		if ( $title ) {
 			echo $args['before_title'] . $title . $args['after_title'];
 		}
+
+		$format = current_theme_supports( 'html5', 'navigation-widgets' ) ? 'html5' : 'xhtml';
+
+		/** This filter is documented in wp-includes/widgets/class-wp-nav-menu-widget.php */
+		$format = apply_filters( 'navigation_widgets_format', $format );
+
+		if ( 'html5' === $format ) {
+			// The title may be filtered: Strip out HTML and make sure the aria-label is never empty.
+			$title      = trim( strip_tags( $title ) );
+			$aria_label = $title ? $title : __( 'RSS Feed' );
+			echo '<nav role="navigation" aria-label="' . esc_attr( $aria_label ) . '">';
+		}
+
 		wp_widget_rss_output( $rss, $instance );
+
+		if ( 'html5' === $format ) {
+			echo '</nav>';
+		}
+
 		echo $args['after_widget'];
 
 		if ( ! is_wp_error( $rss ) ) {
@@ -114,7 +132,7 @@
 	 * @return array Updated settings to save.
 	 */
 	public function update( $new_instance, $old_instance ) {
-		$testurl = ( isset( $new_instance['url'] ) && ( ! isset( $old_instance['url'] ) || ( $new_instance['url'] != $old_instance['url'] ) ) );
+		$testurl = ( isset( $new_instance['url'] ) && ( ! isset( $old_instance['url'] ) || ( $new_instance['url'] !== $old_instance['url'] ) ) );
 		return wp_widget_rss_process( $new_instance, $testurl );
 	}