You are reading an unmaintained version of the Ansible documentation. Unmaintained Ansible versions can contain unfixed security vulnerabilities (CVE). Please upgrade to a maintained version. See the latest Ansible documentation.
Similar to the facter module, this runs the Ohai discovery program (http://wiki.opscode.com/display/chef/Ohai) on the remote host and returns JSON inventory data. Ohai data is a bit more verbose and nested than facter.