diff -r be944660c56a -r 3d72ae0968f4 wp/wp-admin/theme-editor.php
--- a/wp/wp-admin/theme-editor.php	Wed Sep 21 18:19:35 2022 +0200
+++ b/wp/wp-admin/theme-editor.php	Tue Sep 27 16:37:53 2022 +0200
@@ -1,6 +1,6 @@
 <?php
 /**
- * Theme editor administration panel.
+ * Theme file editor administration panel.
  *
  * @package WordPress
  * @subpackage Administration
@@ -18,6 +18,7 @@
 	wp_die( '<p>' . __( 'Sorry, you are not allowed to edit templates for this site.' ) . '</p>' );
 }
 
+// Used in the HTML title tag.
 $title       = __( 'Edit Themes' );
 $parent_file = 'themes.php';
 
@@ -26,9 +27,9 @@
 		'id'      => 'overview',
 		'title'   => __( 'Overview' ),
 		'content' =>
-				'<p>' . __( 'You can use the theme editor to edit the individual CSS and PHP files which make up your theme.' ) . '</p>' .
+				'<p>' . __( 'You can use the theme file editor to edit the individual CSS and PHP files which make up your theme.' ) . '</p>' .
 				'<p>' . __( 'Begin by choosing a theme to edit from the dropdown menu and clicking the Select button. A list then appears of the theme&#8217;s template files. Clicking once on any file name causes the file to appear in the large Editor box.' ) . '</p>' .
-				'<p>' . __( 'For PHP files, you can use the Documentation dropdown to select from functions recognized in that file. Look Up takes you to a web page with reference material about that particular function.' ) . '</p>' .
+				'<p>' . __( 'For PHP files, you can use the documentation dropdown to select from functions recognized in that file. Look Up takes you to a web page with reference material about that particular function.' ) . '</p>' .
 				'<p id="editor-keyboard-trap-help-1">' . __( 'When using a keyboard to navigate:' ) . '</p>' .
 				'<ul>' .
 				'<li id="editor-keyboard-trap-help-2">' . __( 'In the editing area, the Tab key enters a tab character.' ) . '</li>' .
@@ -49,7 +50,7 @@
 get_current_screen()->set_help_sidebar(
 	'<p><strong>' . __( 'For more information:' ) . '</strong></p>' .
 	'<p>' . __( '<a href="https://developer.wordpress.org/themes/">Documentation on Theme Development</a>' ) . '</p>' .
-	'<p>' . __( '<a href="https://wordpress.org/support/article/using-themes/">Documentation on Using Themes</a>' ) . '</p>' .
+	'<p>' . __( '<a href="https://wordpress.org/support/article/appearance-editor-screen/">Documentation on Editing Themes</a>' ) . '</p>' .
 	'<p>' . __( '<a href="https://wordpress.org/support/article/editing-files/">Documentation on Editing Files</a>' ) . '</p>' .
 	'<p>' . __( '<a href="https://developer.wordpress.org/themes/basics/template-tags/">Documentation on Template Tags</a>' ) . '</p>' .
 	'<p>' . __( '<a href="https://wordpress.org/support/">Support</a>' ) . '</p>'
@@ -195,14 +196,14 @@
 	</div>
 <?php endif; ?>
 
-<?php if ( preg_match( '/\.css$/', $file ) ) : ?>
+<?php if ( preg_match( '/\.css$/', $file ) && ! wp_is_block_theme() && current_user_can( 'customize' ) ) : ?>
 	<div id="message" class="notice-info notice">
 		<p><strong><?php _e( 'Did you know?' ); ?></strong></p>
 		<p>
 			<?php
 			printf(
 				/* translators: %s: Link to Custom CSS section in the Customizer. */
-				__( 'There&#8217;s no need to change your CSS here &mdash; you can edit and live preview CSS changes in the <a href="%s">built-in CSS editor</a>.' ),
+				__( 'There is no need to change your CSS here &mdash; you can edit and live preview CSS changes in the <a href="%s">built-in CSS editor</a>.' ),
 				esc_url( add_query_arg( 'autofocus[section]', 'custom_css', admin_url( 'customize.php' ) ) )
 			);
 			?>
@@ -342,10 +343,12 @@
 
 	$excluded_referer_basenames = array( 'theme-editor.php', 'wp-login.php' );
 
-	if ( $referer && ! in_array( basename( parse_url( $referer, PHP_URL_PATH ) ), $excluded_referer_basenames, true ) ) {
-		$return_url = $referer;
-	} else {
-		$return_url = admin_url( '/' );
+	$return_url = admin_url( '/' );
+	if ( $referer ) {
+		$referer_path = parse_url( $referer, PHP_URL_PATH );
+		if ( is_string( $referer_path ) && ! in_array( basename( $referer_path ), $excluded_referer_basenames, true ) ) {
+			$return_url = $referer;
+		}
 	}
 	?>
 	<div id="file-editor-warning" class="notification-dialog-wrap file-editor-warning hide-if-no-js hidden">
@@ -356,7 +359,7 @@
 					<h1><?php _e( 'Heads up!' ); ?></h1>
 					<p>
 						<?php
-						_e( 'You appear to be making direct edits to your theme in the WordPress dashboard. We recommend that you don&#8217;t! Editing your theme directly could break your site and your changes may be lost in future updates.' );
+						_e( 'You appear to be making direct edits to your theme in the WordPress dashboard. It is not recommended! Editing your theme directly could break your site and your changes may be lost in future updates.' );
 						?>
 					</p>
 						<?php