Rocket Validator looks for accesibility violations on your pages using the axe-core accessibility engine, hosted on our own servers and integrated into our web crawler. You don't need to buy an additional license, everything's already included in your Pro account at Rocket Validator.
A11Y check: ARIA roles used must conform to valid values
Accessibility rule: Values assigned to ARIA role values must be valid. Role values must be spelled correctly, correspond to existing ARIA role values, and must not be abstract roles to correctly expose the purpose of the element.