Tips on Customizing Broken Link Checker

How to Hide Broken Link Checker Admin Menus

function plt_hide_broken_link_checker_menus() {
	//Hide the "Tools → Broken Links 1" menu.
	remove_submenu_page('tools.php', 'view-broken-links');
	//Hide the "Settings → Link Checker" menu.
	remove_submenu_page('options-general.php', 'link-checker-settings');
}

add_action('admin_menu', 'plt_hide_broken_link_checker_menus', 11);

Where do I put this code?

How to Hide the "Broken Link Checker" Dashboard Widget

function plt_hide_broken_link_checker_dashboard_widgets() {
	$screen = get_current_screen();
	if ( !$screen ) {
		return;
	}

	//Remove the "Broken Link Checker" widget.
	remove_meta_box('blc_dashboard_widget', 'dashboard', 'normal');
}

add_action('wp_dashboard_setup', 'plt_hide_broken_link_checker_dashboard_widgets', 20);