Link to create a new topic with parsed values in GET-method data?

Feature
1

I’ve found this topic on how to Compose a new, pre-filled topic via URL.

I would like to have the referring URL included in the body. Perhaps via some token parsing in the values passed along as GET-method data in the topic-creating URL, like adding…

body=%37referring_URL%37

I saw mention of this somewhere as I was reading…