diff -r 48c4eec2b7e6 -r 8c2e4d02f4ef wp/wp-includes/blocks/template-part.php
--- a/wp/wp-includes/blocks/template-part.php	Fri Sep 05 18:40:08 2025 +0200
+++ b/wp/wp-includes/blocks/template-part.php	Fri Sep 05 18:52:52 2025 +0200
@@ -70,7 +70,9 @@
 			if ( 0 === validate_file( $attributes['slug'] ) ) {
 				$block_template = get_block_file_template( $template_part_id, 'wp_template_part' );
 
-				$content = $block_template->content;
+				if ( isset( $block_template->content ) ) {
+					$content = $block_template->content;
+				}
 				if ( isset( $block_template->area ) ) {
 					$area = $block_template->area;
 				}