Any Solidity-based sparse merkle tree implemenations in production?

Question

It looks like sparse Merkle trees are useful for proofs in L2 systems. When looking around, a number of projects can be found that implement sparse Merkle trees to authenticate state or account trees.

For security reasons, I'm interested in an audited version of a sparse Merkle tree. Is there a sparse Merkle tree implementation in Solidity that has been running and managing a significant amount of value in production on the Ethereum mainnet? If so, is its implementation open source e.g. on GitHub?

Answer 1

The ETH 2 deposit contract implements a sparse Merkle tree that holds $14B of Ether at the time of writing this answer.