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WCAG: 4.1.2: Required ARIA attributes must be provided
ARIA widget roles must have appropriate attributes describing the state or properties of the widget.
ARIA widget roles require additional attributes that describe the state of the widget. The state of the widget is not communicated to screen reader users if a required attribute is omitted.
Certain roles act as composite user interface widgets. As such, they typically act as containers that manage other, contained widgets. When an object inherits from multiple ancestors and one ancestor indicates support for one property while another ancestor indicates that the same property is required, the property becomes required on the inheriting object. In some cases, default values are sufficient to meet ARIA attribute requirements.
When required state and property attributes for specific roles (and subclass roles) are not present, screen readers may not be able to convey the definition of what the element's role is to the users.