Snippets

function add_manage_patterns_menu() {
    add_submenu_page(
        'themes.php', // Parent slug for Appearance menu
        'Manage Patterns', // Page title
        'Manage Patterns', // Menu title
        'edit_theme_options', // Capability
        'edit.php?post_type=wp_block' // Menu slug
    );
}

add_action('admin_menu', 'add_manage_patterns_menu');