themes-wordpress/pixl/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":"pixl/404"} /-->

</main>
<!-- /wp:group -->

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