Disambiguation: in the Initiation_Setting Group Roles To Shared Space Members, there is a manager role. In this case, I think that another word for “role” can be something like “title”.
In the point of view of the system, this “manager role” is an attribute of the user; the “real” manager (“administrator”) of the shared space can maybe be another person.
My confusion was in-between “group role” (that doesn’t affect the access rights, but makes members of the group agree who do what) and “access rights role” (which affect the shared space administration).
-- Patrick Ausderau