Jenkins stores all the data files inside this directory in the file system. You can change this by either:

1. Using your web container's admin tool to set the `JENKINS_HOME` environment entry.
2. Setting the environment variable `JENKINS_HOME` before launching your web container.
3. (Not recommended) modifying web.xml in `jenkins.war` (or its expanded image in your web container).

This value cannot be changed while Jenkins is running. This entry is mostly for you to make sure that your configuration is taking effect.