Highlight on pages lists in editor if page is having Gutenberg markup or not.

editor-check-gutenberg-markup.php

<?php
function ms_filter_posts_columns( $columns ) {

	$columns['gutenberg_markup'] = __( 'Gutenberg Markup?', 'text-domain' );

	return $columns;
}

function ms_page_column( $column, $post_id ) {

	if ( 'gutenberg_markup' === $column ) {

		if ( preg_match( '/(wp:paragraph|wp:heading|wp:list|wp:cover|wp:image)/i', get_the_content( $post_id ) ) ) {

			echo '<div style="color: green; text-align:center;">&#x2713;</div>';

		} else {
		
			echo '<div style="color: red; text-align:center;">&#x2717;</div>';

		}
	}
}

add_filter( 'manage_page_posts_columns', 'ms_filter_posts_columns' );
add_action( 'manage_page_posts_custom_column', 'ms_page_column', 10, 2);