It is an easy to install plugin for almost all IntelliJ IDEA based IDEs, which turns them into a powerful development tool for Mathematica and Wolfram Language code. The plugin and the Community Edition of IDEA is open-source and therefore completely free of charge.
Set of packages enhancing capabilities of Wolfram Workbench.
Features include, inter alia, creating cross-version compatible documentation and including, in build scripts, test suite runs in multiple Mathematica versions.