The trusted role is the role that can be set up so a user needs it in order to have their birthday celebrated. If the setting
Trusted Prevents Message is enabled/true, then only users with the trusted role will receive a birthday message. Likewise, if the setting
Trusted Prevents Role is enabled/true, then only users with the trusted role will receive the birthday role. Note: if the trusted role itself is not set, none of these settings will apply, and anyone with a birthday set will receive both a birthday message and the birthday role (assuming both are set).