Index: src/wp-includes/script-loader.php
===================================================================
--- src/wp-includes/script-loader.php	(revision 43972)
+++ src/wp-includes/script-loader.php	(working copy)
@@ -1800,6 +1800,9 @@
 
 	$styles->add( 'wp-block-library-theme', "/wp-includes/css/dist/block-library/theme$suffix.css" );
 	$styles->add_data( 'wp-block-library-theme', 'rtl', 'replace' );
+	if ( $suffix ) {
+		$styles->add_data( 'wp-block-library-theme', 'suffix', $suffix );
+	}
 
 	$styles->add(
 		'wp-edit-blocks',
@@ -1812,6 +1815,9 @@
 		)
 	);
 	$styles->add_data( 'wp-edit-blocks', 'rtl', 'replace' );
+	if ( $suffix ) {
+		$styles->add_data( 'wp-edit-blocks', 'suffix', $suffix );
+	}
 
 	$package_styles = array(
 		'block-library' => array(),
@@ -1829,6 +1835,9 @@
 
 		$styles->add( $handle, $path, $dependencies );
 		$styles->add_data( $handle, 'rtl', 'replace' );
+		if ( $suffix ) {
+			$styles->add_data( $handle, 'suffix', $suffix );
+		}
 	}
 }