The highest ranking search result for accessibility auditing tools is accessibilitychecker.org. The design and initial messaging had me suspicious out of the gate, but I didn’t see immediate branding for an overlay company.
That is until I submitted a sample test of Google and saw one of the overlay monsters appear as a recommended solution.
Equally as gross, to my mind, is the “legal action” modal that appears when you attempt to use the “back to home” link.
Don’t fall for this one, folks.