diff -r 34716fd837a4 -r be944660c56a wp/wp-admin/options-permalink.php
--- a/wp/wp-admin/options-permalink.php	Tue Dec 15 15:52:01 2020 +0100
+++ b/wp/wp-admin/options-permalink.php	Wed Sep 21 18:19:35 2022 +0200
@@ -72,7 +72,7 @@
 	$prefix = '/index.php';
 }
 
-/**
+/*
  * In a subdirectory configuration of multisite, the `/blog` prefix is used by
  * default on the main site to avoid collisions with other sites created on that
  * network. If the `permalink_structure` option has been changed to remove this
@@ -82,36 +82,17 @@
 	$blog_prefix = '/blog';
 }
 
-$category_base   = get_option( 'category_base' );
-$tag_base        = get_option( 'tag_base' );
-$update_required = false;
+$category_base = get_option( 'category_base' );
+$tag_base      = get_option( 'tag_base' );
 
-if ( $iis7_permalinks ) {
-	if ( ( ! file_exists( $home_path . 'web.config' ) && win_is_writable( $home_path ) ) || win_is_writable( $home_path . 'web.config' ) ) {
-		$writable = true;
-	} else {
-		$writable = false;
-	}
-} elseif ( $is_nginx ) {
-	$writable = false;
-} else {
-	if ( ( ! file_exists( $home_path . '.htaccess' ) && is_writable( $home_path ) ) || is_writable( $home_path . '.htaccess' ) ) {
-		$writable = true;
-	} else {
-		$writable        = false;
-		$existing_rules  = array_filter( extract_from_markers( $home_path . '.htaccess', 'WordPress' ) );
-		$new_rules       = array_filter( explode( "\n", $wp_rewrite->mod_rewrite_rules() ) );
-		$update_required = ( $new_rules !== $existing_rules );
-	}
-}
-
-$using_index_permalinks = $wp_rewrite->using_index_permalinks();
+$structure_updated        = false;
+$htaccess_update_required = false;
 
 if ( isset( $_POST['permalink_structure'] ) || isset( $_POST['category_base'] ) ) {
 	check_admin_referer( 'update-permalink' );
 
 	if ( isset( $_POST['permalink_structure'] ) ) {
-		if ( isset( $_POST['selection'] ) && 'custom' != $_POST['selection'] ) {
+		if ( isset( $_POST['selection'] ) && 'custom' !== $_POST['selection'] ) {
 			$permalink_structure = $_POST['selection'];
 		} else {
 			$permalink_structure = $_POST['permalink_structure'];
@@ -129,46 +110,78 @@
 		$permalink_structure = sanitize_option( 'permalink_structure', $permalink_structure );
 
 		$wp_rewrite->set_permalink_structure( $permalink_structure );
+
+		$structure_updated = true;
 	}
 
 	if ( isset( $_POST['category_base'] ) ) {
 		$category_base = $_POST['category_base'];
+
 		if ( ! empty( $category_base ) ) {
 			$category_base = $blog_prefix . preg_replace( '#/+#', '/', '/' . str_replace( '#', '', $category_base ) );
 		}
+
 		$wp_rewrite->set_category_base( $category_base );
 	}
 
 	if ( isset( $_POST['tag_base'] ) ) {
 		$tag_base = $_POST['tag_base'];
+
 		if ( ! empty( $tag_base ) ) {
 			$tag_base = $blog_prefix . preg_replace( '#/+#', '/', '/' . str_replace( '#', '', $tag_base ) );
 		}
+
 		$wp_rewrite->set_tag_base( $tag_base );
 	}
+}
 
+if ( $iis7_permalinks ) {
+	if ( ( ! file_exists( $home_path . 'web.config' ) && win_is_writable( $home_path ) ) || win_is_writable( $home_path . 'web.config' ) ) {
+		$writable = true;
+	} else {
+		$writable = false;
+	}
+} elseif ( $is_nginx ) {
+	$writable = false;
+} else {
+	if ( ( ! file_exists( $home_path . '.htaccess' ) && is_writable( $home_path ) ) || is_writable( $home_path . '.htaccess' ) ) {
+		$writable = true;
+	} else {
+		$writable       = false;
+		$existing_rules = array_filter( extract_from_markers( $home_path . '.htaccess', 'WordPress' ) );
+		$new_rules      = array_filter( explode( "\n", $wp_rewrite->mod_rewrite_rules() ) );
+
+		$htaccess_update_required = ( $new_rules !== $existing_rules );
+	}
+}
+
+$using_index_permalinks = $wp_rewrite->using_index_permalinks();
+
+if ( $structure_updated ) {
 	$message = __( 'Permalink structure updated.' );
 
-	if ( $iis7_permalinks ) {
-		if ( $permalink_structure && ! $using_index_permalinks && ! $writable ) {
+	if ( ! is_multisite() && $permalink_structure && ! $using_index_permalinks ) {
+		if ( $iis7_permalinks ) {
+			if ( ! $writable ) {
+				$message = sprintf(
+					/* translators: %s: web.config */
+					__( 'You should update your %s file now.' ),
+					'<code>web.config</code>'
+				);
+			} else {
+				$message = sprintf(
+					/* translators: %s: web.config */
+					__( 'Permalink structure updated. Remove write access on %s file now!' ),
+					'<code>web.config</code>'
+				);
+			}
+		} elseif ( ! $is_nginx && $htaccess_update_required && ! $writable ) {
 			$message = sprintf(
-				/* translators: %s: web.config */
+				/* translators: %s: .htaccess */
 				__( 'You should update your %s file now.' ),
-				'<code>web.config</code>'
-			);
-		} elseif ( $permalink_structure && ! $using_index_permalinks && $writable ) {
-			$message = sprintf(
-				/* translators: %s: web.config */
-				__( 'Permalink structure updated. Remove write access on %s file now!' ),
-				'<code>web.config</code>'
+				'<code>.htaccess</code>'
 			);
 		}
-	} elseif ( ! $is_nginx && $permalink_structure && ! $using_index_permalinks && ! $writable && $update_required ) {
-		$message = sprintf(
-			/* translators: %s: .htaccess */
-			__( 'You should update your %s file now.' ),
-			'<code>.htaccess</code>'
-		);
 	}
 
 	if ( ! get_settings_errors() ) {
@@ -344,7 +357,7 @@
 		if ( isset( $_POST['submit'] ) && $permalink_structure && ! $using_index_permalinks && ! $writable ) :
 			if ( file_exists( $home_path . 'web.config' ) ) :
 				?>
-<p>
+<p id="iis-description-a">
 				<?php
 				printf(
 					/* translators: 1: web.config, 2: Documentation URL, 3: CTRL + a, 4: Element code. */
@@ -358,7 +371,7 @@
 </p>
 <form action="options-permalink.php" method="post">
 				<?php wp_nonce_field( 'update-permalink' ); ?>
-	<p><textarea rows="9" class="large-text readonly" name="rules" id="rules" readonly="readonly"><?php echo esc_textarea( $wp_rewrite->iis7_url_rewrite_rules() ); ?></textarea></p>
+	<p><label for="rules"><?php _e( 'Rewrite rules:' ); ?></label><br /><textarea rows="9" class="large-text readonly" name="rules" id="rules" readonly="readonly" aria-describedby="iis-description-a"><?php echo esc_textarea( $wp_rewrite->iis7_url_rewrite_rules() ); ?></textarea></p>
 </form>
 <p>
 				<?php
@@ -370,7 +383,7 @@
 				?>
 </p>
 		<?php else : ?>
-<p>
+<p id="iis-description-b">
 			<?php
 			printf(
 				/* translators: 1: Documentation URL, 2: web.config, 3: CTRL + a */
@@ -383,7 +396,7 @@
 </p>
 <form action="options-permalink.php" method="post">
 			<?php wp_nonce_field( 'update-permalink' ); ?>
-	<p><textarea rows="18" class="large-text readonly" name="rules" id="rules" readonly="readonly"><?php echo esc_textarea( $wp_rewrite->iis7_url_rewrite_rules( true ) ); ?></textarea></p>
+	<p><label for="rules"><?php _e( 'Rewrite rules:' ); ?></label><br /><textarea rows="18" class="large-text readonly" name="rules" id="rules" readonly="readonly" aria-describedby="iis-description-b"><?php echo esc_textarea( $wp_rewrite->iis7_url_rewrite_rules( true ) ); ?></textarea></p>
 </form>
 <p>
 			<?php
@@ -400,9 +413,9 @@
 	<p><?php _e( '<a href="https://wordpress.org/support/article/nginx/">Documentation on Nginx configuration</a>.' ); ?></p>
 	<?php
 else :
-	if ( $permalink_structure && ! $using_index_permalinks && ! $writable && $update_required ) :
+	if ( $permalink_structure && ! $using_index_permalinks && ! $writable && $htaccess_update_required ) :
 		?>
-<p>
+<p id="htaccess-description">
 		<?php
 		printf(
 			/* translators: 1: .htaccess, 2: Documentation URL, 3: CTRL + a */
@@ -415,7 +428,7 @@
 </p>
 <form action="options-permalink.php" method="post">
 		<?php wp_nonce_field( 'update-permalink' ); ?>
-	<p><textarea rows="6" class="large-text readonly" name="rules" id="rules" readonly="readonly"><?php echo esc_textarea( $wp_rewrite->mod_rewrite_rules() ); ?></textarea></p>
+	<p><label for="rules"><?php _e( 'Rewrite rules:' ); ?></label><br /><textarea rows="8" class="large-text readonly" name="rules" id="rules" readonly="readonly" aria-describedby="htaccess-description"><?php echo esc_textarea( $wp_rewrite->mod_rewrite_rules() ); ?></textarea></p>
 </form>
 	<?php endif; ?>
 <?php endif; ?>