At the bottom of topics list (viewforum.php), anonymous and logged users can view their permissions for a given forum.

However, if a logged/registered user cannot post a new topic (regardless the other permission, such as replying to the existing topics), the forum permissions don't appear at all. The bug doesn't occur for anonymous users.

The problem is due to the S_DISPLAY_POST_INFO template variable, because it's the condition to display the permissions list in viewforum_body.html ; S_DISPLAY_POST_INFO is also used to hide posting button for logged users who aren't allowed to post a new topic, and still display that button for anonymous users, even if they cannot post new topic without registration/loggin.