HTML Checking for Large Sites
Rocket Validator automatically checks your pages on the W3C Validator.
HTML issues tagged as aria-describedby.
The aria-describedby attribute is used to indicate the IDs of the elements that describe the object. It should reference an existing ID on the same document, but that id was not found.
When was the last time you validated your whole site?
Keep your sites healthy checking for A11Y/HTML issues on an automated schedule.