Hi there,
For now you can make changes on core file, later on theme update we will make this things available.
Their on functions.php file you can find puresimple_scripts() function and their you can find whole js that are added on theme. For an example:
wp_enqueue_script( 'puresimple-jquery-ui', get_template_directory_uri() . '/js/jquery-ui.js', array( 'jquery' ), '1.0',TRUE);
You can take this article to know more on wp_enqueue_script function :
https://developer.wordpress.org/reference/functions/wp_enqueue_script/
We hope this will help you.
Thanks