This requires more clarification.
p7zip-full , rar and unrar are detected by most archive managers which are used by most modern desktop environments, MATE's engrampa included.
This is important to understand; these are command-line utilities that Engrampa, as an archive manager and frontend for the novice to browse and view files in a GUI seek out. This check is performed before rendering the interface, which make them appear in the list of available formats for creation if a corresponding library it checks for exists.