Course Roles

This is a role that is assigned at the management level. 

The default Manager role enables users assigned the role to access courses and modify them, as well as perform certain administrative level tasks related to courses, users, grade settings, etc.

Unlike the administrator role, the Manager role is a 'real role', whose capabilities you can edit, but is similar to Administrator (but much safer to use) due to its broad default powers. As a normal role, like Course Creator or Teacher, while the Manager role has almost very many capabilities by default, you can edit that role if you choose.

(The way permission checks work in the Moodle code is that there is a function called has_capability. For admins, has_capability will always return true, no matter how the roles are set up. Thus there is no way to edit what permissions an Administrator has.)

Adopting a best-practice based on the Principle of Least Privilege suggests that Admins should normally use a Manager role, and not use an Administrator account, similar to the way you are recommended not to log into Linux as root.

The Manager role therefore allows a site Administrator to give very powerful roles to others who are assigned a Manager role, but without having to give them a full Administrator role.