I honestly don’t know. It’s possible that the MODX code will add one if it’s necessary. You could try adding one and make a quick test of whether it still works.
The http_host is always without slash or protocol.
server_protocol + http_host + base_url == site_url
https:// + modmore.com + / == https://modmore.com
Thanks Mark. I was unaware of that exception to the general rule.