JSON (JavaScript Object Notation) is a data-interchange format which is mainly pitched as being easy for machines to parse and generate. It also gets used a lot by human eyeballs for configuration files. Besides being significantly less human-friendly than, say, YAML, there’s a vast pile of tooling to make it less of a nightmare to deal with. jq is most of the kit you need to deal with it as a consumer, so I highly recommend it. As a producer, I’d be happier with Dhall.