Definition

Accessibility overlay

A widget added in one line of code that claims to make a site compliant. It does not fix the source code and is increasingly contested.

An overlay is a software layer placed on top of an existing site. Vendors promise instant compliance, but the overlay does not fix the problems in the source code.

Why they are a problem

They create a false sense of compliance, can hinder screen-reader users and are the subject of criticism and litigation. The durable route is to fix issues at the source, then publish an honest statement.