In some cases it may be desirable to hide a folder, while still making files inside it accessible.
For example, a course site owner may wish to include various images in the Wiki, but doesn't want a 'WikiImages' folder visible to students browsing the site.
Folders (optionally files) should therefore have an attribute which can be set by someone with appropriate permissions on the folder, viz. 'Hidden'. Hidden folders are displayed to users who have update permissions on the folder, but are not displayed to users who have read-only access.