Homeassistant.external:url in templates?

Hi Community,

I currently working on getting external access working. For that I would like to automate the process for updating the DNS record on my own domain. I have REST API access to the DNS server responsible for my domain.

My plan is to use an automation to update the DNS record with the IPv6 address if changed.
The IPv6 Address I‘m already getting.
Is there any way to get the configured External_URL to be used in a template? Currently I‘m using an additional input_text but then I have to change the URL on two points if I want to change them… I‘m not a friend of unnecessary redundancy, and maybe it‘s interesting to learn how to access the configuration metadata of home assistant.