This top-level /accessibility directory contains primarily (only?) general crash tests.
Accessibility specs are tested in top-level directories named after the particular spec. For example, see automated accessibility tests in:
/wai-aria/html-aam/accname- etc.
Primary reviewers for each of those specs can often be found in the META.yml file in each respective directory. Reach out directly or file related issues in each spec repo.
Pull requests welcome. Thank you!