themes-wordpress/mysa/patterns/header.php

<?php
/**
 * Title: Default header
 * Slug: mysa/header
 * Categories: header
 * Block Types: core/template-part/header
 */

declare( strict_types = 1 );
?>

<!-- wp:group {"layout":{"type":"default"}} -->
<div class="wp-block-group">
	<!-- wp:site-title {"level":0} /-->

	<!-- wp:group {"layout":{"type":"flex","orientation":"vertical"}} -->
	<div class="wp-block-group">
		<!-- wp:navigation {"overlayBackgroundColor":"background","overlayTextColor":"foreground","layout":{"type":"flex","orientation":"vertical","justifyContent":"left"},"style":{"spacing":{"blockGap":"0"}}} /-->
	</div>
	<!-- /wp:group -->
</div>
<!-- /wp:group -->