Maybe I have something similar here: the category should be readable for anyone. Creation of new topics and edits should only be able for users with “wiki” group permissions. In fact it is readable without a login. Then just the info “category is private …“ is wrong and should read “category has permission limits, only the selected groups can create and reply posts” instead.
Note that the category is federated at wiki@forum.netzwissen.de with public visibility.
