Gwenhywfar is a base library used to provide OS abstraction functions for Linux, FreeBSD, OpenBSD, NetBSD, and Windows. It also includes some often needed functions (for example, handling and parsing of configuration files, reading and writing of XML files, and interprocess communication).

JSON is a lightweight data-interchange format. It can represent numbers,
strings, ordered sequences of values, and collections of name/value pairs.

JsonCpp is a C++ library that allows manipulating JSON values, including
serialization and deserialization to and from strings. It can also preserve
existing comment in unserialization/serialization steps, making it a convenient
format to store user input files.