Yes, I'm familiar with Libbitcoin. Libbitcoin is an open-source C++ Bitcoin library that provides a variety of functionalities for developers to work with the Bitcoin protocol. It offers a set of tools, APIs, and cryptographic primitives to interact with the Bitcoin network and build Bitcoin-related applications. Libbitcoin aims to provide a flexible and modular framework for developers to create their own Bitcoin software, ranging from lightweight wallets to full nodes. It supports various features such as key management, transaction creation and validation, scripting, networking, and blockchain analysis.