diff -r be944660c56a -r 3d72ae0968f4 wp/wp-includes/blocks/post-comments.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/blocks/post-comments.php	Tue Sep 27 16:37:53 2022 +0200
@@ -0,0 +1,85 @@
+<?php
+/**
+ * Server-side rendering of the `core/post-comments` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Renders the `core/post-comments` block on the server.
+ *
+ * @param array    $attributes Block attributes.
+ * @param string   $content    Block default content.
+ * @param WP_Block $block      Block instance.
+ * @return string Returns the filtered post comments for the current post wrapped inside "p" tags.
+ */
+function render_block_core_post_comments( $attributes, $content, $block ) {
+	global $post;
+
+	$post_id = $block->context['postId'];
+	if ( ! isset( $post_id ) ) {
+		return '';
+	}
+
+	$comment_args = array(
+		'post_id' => $post_id,
+		'count'   => true,
+	);
+	// Return early if there are no comments and comments are closed.
+	if ( ! comments_open( $post_id ) && get_comments( $comment_args ) === 0 ) {
+		return '';
+	}
+
+	$post_before = $post;
+	$post        = get_post( $post_id );
+	setup_postdata( $post );
+
+	ob_start();
+	// There's a deprecation warning generated by WP Core.
+	// Ideally this deprecation is removed from Core.
+	// In the meantime, this removes it from the output.
+	add_filter( 'deprecated_file_trigger_error', '__return_false' );
+	comments_template();
+	remove_filter( 'deprecated_file_trigger_error', '__return_false' );
+	$post = $post_before;
+
+	$classes = '';
+	if ( isset( $attributes['textAlign'] ) ) {
+		$classes .= 'has-text-align-' . $attributes['textAlign'];
+	}
+
+	$wrapper_attributes = get_block_wrapper_attributes( array( 'class' => $classes ) );
+	$output             = ob_get_clean();
+
+	return sprintf( '<div %1$s>%2$s</div>', $wrapper_attributes, $output );
+}
+
+/**
+ * Registers the `core/post-comments` block on the server.
+ */
+function register_block_core_post_comments() {
+	register_block_type_from_metadata(
+		__DIR__ . '/post-comments',
+		array(
+			'render_callback' => 'render_block_core_post_comments',
+		)
+	);
+}
+add_action( 'init', 'register_block_core_post_comments' );
+
+/**
+ * Use the button block classes for the form-submit button.
+ *
+ * @param array $fields The default comment form arguments.
+ *
+ * @return array Returns the modified fields.
+ */
+function post_comments_block_form_defaults( $fields ) {
+	if ( wp_is_block_theme() ) {
+		$fields['submit_button'] = '<input name="%1$s" type="submit" id="%2$s" class="%3$s wp-block-button__link" value="%4$s" />';
+		$fields['submit_field']  = '<p class="form-submit wp-block-button">%1$s %2$s</p>';
+	}
+
+	return $fields;
+}
+add_filter( 'comment_form_defaults', 'post_comments_block_form_defaults' );