Non-mandatory relationship in MySQL Workbench ERD

From the MySQL manual:

8.1.4.2 The Relationship Editor Double-clicking a relationship on theEER diagram canvas opens the relationship editor. This has two tabs: Relationship, and Foreign Key.

The Foreign Key tab contains several sections: Referencing Table, Cardinality and Referenced Table. The Mandatory check boxes are used to select whether the referencing table and the referenced table are mandatory. By default, both of these constraints are true (indicated by the check boxes being checked). The Cardinality section has a set of radio buttons that enable you to choose whether the relationship is one-to-one or one-to-many. There is also a check box that enables you to specify whether the relationship is an identifying relationship.