@tante
A while back I found an essay titled "Healthy expectations in open source" by @donmccurdy that proposes just such a standard:
https://www.donmccurdy.com/2023/07/03/expectations-in-open-source/
I found the classifications well thought out and have started to use it for my own small projects.
This was the accompanying Fediverse post: https://fosstodon.org/@donmccurdy/110662029314944366