Holešky testnet, launched by Ethereum developers on September 15, has a supply of 1.6 billion ETH, making it more accessible than the older Goerli network. It is expected to be used for staking, infrastructure, and protocol development. Sepolia will remain the dominant network for application development. The large initial supply of Holešky testnet Ether (HETH) aims to address the low supply issue faced by Goerli testnet. Ethereum developers have been urging application developers to move from Goerli to Sepolia, and Goerli is planned to be deprecated in January 2024. Holešky will play a crucial role in trialing various features before implementing them on the mainnet.