Restricted admin defines a user which is not an admin but is able to manage any user who has less than or equal access rights as himself. The setting for marking given user as a restricted admin can be found at the bottom of the user edit page (see picture below).
By checking the checkbox “Can manage users” given user gains access to edit other users who have less than or equal access rights as himself.
These access rights can be used efficiently for giving for example Area managers or Country managers the ability to edit the users within their Area and Country respectively.
If restricted admin has a role, the user must also have a role and restricted admins own places must contain the users own places.
If restricted admin doesn't have a role, the user must also not have a role.
In both cases restricted admin can only give the user access rights which are less than or equal access right as himself.