Ember.AriaRoleSupport Class packages/ember-views/lib/mixins/aria_role_support.js:8
The WAI-ARIA role of the control represented by this view. For example, a button may have a role of type 'button', or a pane may have a role of type 'alertdialog'. This property is used by assistive software to help visually challenged users navigate rich web applications.
The full list of valid WAI-ARIA roles is available at: http://www.w3.org/TR/wai-aria/roles#roles_categorization