TOML
Tom Preston-Werner's obvious, minimal language
...TOML shares traits with other file formats used for application configuration and data serialization, such as YAML and JSON. TOML and JSON both are simple and use ubiquitous data types, making them easy to code for or parse with machines. TOML and YAML both emphasize human readability features, like comments that make it easier to understand the purpose of a given line. TOML differs in combining these, allowing comments (unlike JSON) but preserving simplicity (unlike YAML). Because TOML is explicitly intended as a configuration file format, parsing it is easy, but it is not intended for serializing arbitrary data structures.