diff --git a/src/wp-admin/edit-form-blocks.php b/src/wp-admin/edit-form-blocks.php
index 3aead40a7b..71328d0ad5 100644
--- a/src/wp-admin/edit-form-blocks.php
+++ b/src/wp-admin/edit-form-blocks.php
@@ -131,7 +131,8 @@ $available_templates = ! empty( $available_templates ) ? array_merge(
 // Editor Styles.
 $styles = array(
 	array(
-		'css' => 'body { font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif }',
+		'css'            => 'body { font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif }',
+		'__unstableType' => 'core',
 	),
 );
 if ( $editor_styles && current_theme_supports( 'editor-styles' ) ) {
@@ -140,15 +141,17 @@ if ( $editor_styles && current_theme_supports( 'editor-styles' ) ) {
 			$response = wp_remote_get( $style );
 			if ( ! is_wp_error( $response ) ) {
 				$styles[] = array(
-					'css' => wp_remote_retrieve_body( $response ),
+					'css'            => wp_remote_retrieve_body( $response ),
+					'__unstableType' => 'theme',
 				);
 			}
 		} else {
 			$file = get_theme_file_path( $style );
 			if ( is_file( $file ) ) {
 				$styles[] = array(
-					'css'     => file_get_contents( $file ),
-					'baseURL' => get_theme_file_uri( $style ),
+					'css'            => file_get_contents( $file ),
+					'baseURL'        => get_theme_file_uri( $style ),
+					'__unstableType' => 'theme',
 				);
 			}
 		}
diff --git a/src/wp-includes/block-editor.php b/src/wp-includes/block-editor.php
index 3234c4ad1f..101cc1ba71 100644
--- a/src/wp-includes/block-editor.php
+++ b/src/wp-includes/block-editor.php
@@ -283,10 +283,14 @@ function get_block_editor_settings( array $custom_settings, $block_editor_contex
 	$theme_json = WP_Theme_JSON_Resolver::get_merged_data( $editor_settings );
 
 	if ( WP_Theme_JSON_Resolver::theme_has_support() ) {
-		$editor_settings['styles'][] = array( 'css' => $theme_json->get_stylesheet( 'block_styles' ) );
+		$editor_settings['styles'][] = array(
+			'css'            => $theme_json->get_stylesheet( 'block_styles' ),
+			'__unstableType' => 'globalStyles',
+		);
 		$editor_settings['styles'][] = array(
 			'css'                     => $theme_json->get_stylesheet( 'css_variables' ),
 			'__experimentalNoWrapper' => true,
+			'__unstableType'          => 'globalStyles',
 		);
 	}