A library implementing the UCI (Universal Chess Interface) protocol for chess engines.
The goal is to implement a library that handles the communication protocol so that someone wanting to implement a chess engine can focus on the chess-part of the engine, rather than the details of a communication protocol. Some of the most popular chess engines have the UCI part of the engine baked into the rest of the chess engine, making it difficult to re-use. The main benefit of baking the communication protocol into the rest of the engine is that it allows for closer integration with the actual engine, but it's very feasible carving out the part that handles the communication protocol into a separate component without trading-off too much. Also, the UCI protocol is clunky, not well-documented, and difficult to understand. Having a proper library relieves users from having to waste time chasing down bits and pieces from the web to figure out how the protocol actually works.