Capabilities/block/email list:createfolder
From MoodleDocs
This allows a user to create subfolders for inbox and sendbox folders.
Why?
This capability was created to prevent guest users to create subfolders in the site.
Note: You are currently viewing documentation for Moodle 2.9. Up-to-date documentation for the latest stable version of Moodle may be available here: Capabilities/block/email list:createfolder.
