Before (before 4.0 I think), you needed at least an accountability to create a role. In 4.0, you need just a name to define a role because Brian said “a role has a purpose, wether it is explicit or not” and now in 4.1, you need at least one of the elements.
A good practice is to define a role with a purpose to begin with. Accountabilities are not here to describe the role's work, the purpose is here to define the identity of the role.
Understood. So every role needs a name, and in theory you could have a role with just a name and domain (based on the Constitution's phrasing).