I read about this issue on private files for students on moodle 2.3 docs FAQ. https://docs.moodle.org/23/en/Repositories_FAQ
But when defining a new "no private files" role, there are no settings as described here
"moodle/user:manageownfiles and repository/user:view to prohibit"
Can someone please update the docs or help me set the corrects settings to have private files enabled for teacher but not for studendts.