I think (if I understand your comment correctly), mine is the other way around. I want to always be able to go to an easy to remember URL whenever I want to look up the community's policies.

This would (likely) be the same as whichever link a community admin wants a newly-joined user to see.

But my main reason for wanting this canonical URL is for any point afterwards, when I'm in the middle of writing an entry, and I want to look up something in the community's policy post quickly (posting template, tag to use, whether something is allowed or not, etc). Usually, I'd need to go to the community's profile and scan past the other profile information for any links to guidelines. Or I'd go to the community's tag page, and look for any admin/policy/whatever tag, and click through then scan for the entry I want.

I'd like to take out all the middle steps, and simply be able to quickly pull up the main policy entry with (hopefully) the information I need.