'junit' is the legacy Chef InSpec JUnit reporter. It generates nonstandard JUNit XML in several ways. New users are advised to use junit2.
'junit2' is an updated reporter that attempts to match the JUnit "standard", such as it isn't, more closely. It validates against the schema published by [Windy Road](https://github.com/windyroad/JUnit-Schema).
This reporter uses the REXML XML generator, but may use more advanced XML systems for testing. This is to keep packaging requirements for Chef InSpec lightweight and free of compiled dependencies.