The configuration properties for the Guest and SuperaAdmin virtual users can now be overridden. This is achieved by modifying the xwiki.properties file.
For example:
user.preferences.superadmin.editor = Wysiwyg
user.preferences.guest.editor = Text
user.preferences.guest.displayHiddenDocuments = 1
user.preferences.guest.editor = Text
user.preferences.guest.displayHiddenDocuments = 1