JSON (JavaScript Object Notation) is a lightweight data-interchange format.
It can represents integer, real number, string, an ordered sequence of
value, and a collection of name/value pairs.

QJson is a qt-based library that maps JSON data to QVariant objects: JSON
arrays will be mapped to QVariantList instances, while JSON objects will
be mapped to QVariantMap.

The upstream repository is archived:

  This project is archived. QJson was originally created when Qt3 and
  Qt4 lacked robust JSON support.  Since Qt5, JSON support is included
  in the native Qt library SDK, making this project obsolete.