How to find and remove unnecessary theme scripts? [closed]

You should locate all wp_register_script instances (they can be incuded in core, plugin, theme, anywhere) and in your functions.php you can deregister them

add_action( 'wp_enqueue_scripts', 'my_scripts_method' );
function my_scripts_method() {
    // if you want to exclude built-in jQuery
    wp_deregister_script('jquery');
}

All scripts that can be enqueued by WordPress are listed (there are handles of each) in codex