From Fedora Project Wiki
Question
The text says that the root (/) of cups may be provided without authentication, But then in the example config file given it says "Require valid-user".
The cups man page says that Require valid-user means that the user of the resource must be authenticated (that they be a user on the server's system, and so that they provide their user-name and password.)
(I'm not a CUPS novice, so I might be wrong.)