WordPress/wp-includes/blocks/index.php

<?php
/**
 * Used to set up all core blocks used with the block editor.
 *
 * @package WordPress
 */

define( 'BLOCKS_PATH', ABSPATH . WPINC . '/blocks/' );

// Include files required for core blocks registration.
require BLOCKS_PATH . 'legacy-widget.php';
require BLOCKS_PATH . 'widget-group.php';
require BLOCKS_PATH . 'require-dynamic-blocks.php';

/**
 * Registers core block types using metadata files.
 * Dynamic core blocks are registered separately.
 *
 * @since 5.5.0
 */
function register_core_block_types_from_metadata() {
	$block_folders = require BLOCKS_PATH . 'require-static-blocks.php';
	foreach ( $block_folders as $block_folder ) {
		register_block_type(
			BLOCKS_PATH . $block_folder
		);
	}
}
add_action( 'init', 'register_core_block_types_from_metadata' );