What is an appraisal contingency in a real estate contract?

[Benny]

I'm confused, is the appraisal contingency not part of the financing, or mortgage contingency? Is it standard language and automatically assumed to be part of the financing contingency if you ask for one when making an offer?

Or does it need to be negotiated into the contract by your lawyer, and only if you ask for it? Just trying to see what is standard. And helpful if anyone can share sample contract language for an appraisal contingency.