What can this feature do :
A wiki post/admin wiki post is a special type of post that can be edited by any user on your forum.
How do I create (or remove) a wiki post?
To turn a regular post into a wiki post 759 you usually need moderator/admin privileges.
However normal users may also make their post Wiki, provided their trust level is high enough.Admins can change the trust level required with the site setting min trust to allow self wiki.
This is a wikipost
Information got from Discourse FAQ
Yeah, I don’t have it.