Implementation of the FlyClient verification protocol

[Metalcape]

I would like to ask about the current state of the implementation of the FlyClient protocol in zebrad. According to ZIP 221, the blockchain already implements the MMR root hash in the block header (in the form of the blockcommitments field) which could be used by a sublinear client to verify an MMR proof provided by a full node. However, there does not seem to be at the moment any way to generate and share such a proof, because the MMR tree nodes are exclusively used by full nodes internally, and only the root hash is exposed to clients. Are there any plans to implement a way for clients to request an MMR proof for a given block? Could it be done through lightwalled with a new RPC command?

[mpguerra]

We don't currently expose a way to generate and share such a proof in Zebra and we have no plans to do so in the near term as we are fully focused on ensuring that zebra can replace zcashd. Feel free to open up an issue describing your use case and we can consider it as a potential feature in future.