The platform independent Unity3d installation path. This path will be suffixed by "Editor/Unity.exe" on Windows and "Contents/MacOS/Unity" on Mac by the plugin.
This field is optional on the jenkins master if you do not intend to build with unity3d on the master. Do not forget to configure the location of the installations on your nodes as needed.
You may use environment variables in the path and define those variables wherever you feel like (master, node, job). The final installation path will be resolved at job execution time.