I see, I see. And what is a SNARK proving system?

This paper is a great resource if you're unfamiliar with zk-SNARK and how it works:

Why and How zk-SNARK Works (2019)

https://arxiv.org/abs/1906.07221

"Succinct Non-interactive Arguments of Knowledge", it's a system for zero-knowledge proofs, which allow proving a fact of some kind without disclosing the inputs