The eth_getUncleCountByBlockHash method is an Sonic JSON-RPC method that returns the number of uncles in a specified block by its hash. This method can be useful for gathering information about the performance of the Sonic network and to analyse the security of the blockchain.

Uncles are blocks that are not included in the main blockchain but are still valid, and they contribute to the overall security and decentralisation of the Sonic network. The inclusion of uncles helps prevent centralisation and ensures the mining process remains competitive.