Validator website does not have full docment and reference?

Validator website does not have full docment and reference?

While looking for a solution using Validator, I came across to this link on using Validator.element(). Also interested in the Validator.elements(), so I used the URL https://jqueryvalidation.org/Validator.elements . Invalid page. Poked around the Validator website for document/reference, but neither the document nor reference menu link at top provide any details. Tried Categories at right didn't get it.
Is it somewhere or this hard-to-find-things is a natural byproduct of open-source?