Ask HN: Standardized format for longer email (async messages) for humans

A (scrum) story is often written in the form "As a <usertype>, I would like <feature request>, so that <benefit>". Spec by example is written in the format Given <condition>, When <condition>, then <condition>. These are effective formats for capturing complex concepts.

I was wondering if anyone has tried some standardized format that maximizes comprehension of emails or longer async communication in an organization. In a previous (big) organization that I used to work, massive email threads would continue for weeks. More and more distribution groups would start getting added as dependencies were discovered trying to address knowledge gap. Often to make any sense you would have to read bottom up to even understand if it needed your immediate attention/action.

I'm not trying to understand how slack or its clones are solving this problem. Rather looking for any reference of message exchange format for humans that maximizes comprehension.