“wpcargo_after_package_details_script” hook is used to add customized script for the package details section.
add_action('wpcargo_after_package_details_script', 'wpcargo_after_package_details_script_custom_callback', 10, 1 );
function wpcargo_after_package_details_script_custom_callback( $shipment ){
?>
<script>
// You can add your custom script here.
</script>
<?php
}