There is Accessibility field in Section/Control etc., which is available only when Auto-Generated HTML is not selected. From help, we understand that it is being used in accessibility compliance report. Apart from accessibility compliance report, is this field being used any where else or it is used just to indicate that you have designed and implemented HTML to meet our accessibility requirements?
These fields are used to determine accessibility roles and support Accessibility.
Pega provides OOTB accessibility feature through a WAI package, which developer has to import in their application and then run the respective JAWS or other software for reading the inbuilt meta tags in UI for exploiting accessibility features.
Refer these links and embedded sublinks to understand in detailed way:-