Where are the client role mappers?

I want to map a client role to the id token sent to clients.
In earlier versions of Keycloak I could create role mappers for Clients by selecting the Client in the Admin UI and then the tab Role mappers. Now in version 20 this tab does not exist and there is a link to a service account user. But I can’t find a way to create such a mapper on the service account.

Is there any migration guide och documentation that covers this?