The Jenkins "Job DSL / Plugin" is made up of two parts: The Domain Specific Language (DSL) that allows users to describe Jobs using in a groovy-based language, and a Jenkins Plugin which manages the scripts and the updating of the Jenkins jobs which are created and maintained as a result.
This project has moved to jenkinsci/job-dsl-plugin. This repo is no longer updated, yet the issue tracker is still used for the project.