themes-wordpress/remote/templates/404.html

<!-- wp:template-part {"slug":"header","tagName":"header"} /-->

<!-- wp:group {"tagName":"main", "layout":{"inherit":true}} -->
<main class="wp-block-group">
<!-- wp:pattern {"slug":"remote/hidden-404-content"} /-->
</main>
<!-- /wp:group -->

<!-- wp:template-part {"slug":"footer","tagName":"footer","layout":{"inherit":true}} /-->