Remaining Open Form API related Accessibility Issues

https://www.drupal.org/project/form_style →
this module was used for related manual testing during D8/IFE development work. best used alongside disable_html5_validation →

The worst apparent fault is in Vertical Tabs children do not get links from IFE Header (04.2024). Fieldset and Details (own elements) work as generally expected (open with error.

also in contrib:
https://www.drupal.org/project/a11y_form_helpers →
works toward some related aria. (also has 'disable_html5' routine built in.

Test items are returning as expected overall. Top Message (with on page links) are not in the order of the form items themselves. Because of this vertical tabs items are mixed into the list of items, rather than being the last one.