Limit which environment variables are passed to a build step.

Environment variables passed to the build step are filtered, unless listed below.

The behavior of this filter depends on whether the environment variable is originally defined outside Jenkins:

- If the environment variable originates from Jenkins configuration, such as `JOB_URL`, it will not be passed to the build step unless specified here.
- If the environment variable originates from outside Jenkins, such as `PATH`, the behavior depends on the option Process environment variables handling: If that option is set to Retain, the original value will be passed to the build step, discarding any modifications inside Jenkins. If that option is set to Remove, the variable will not be passed to the build step.

The following table shows the effect of filtering on an environment variable:

Behavior | Originally defined outside Jenkins | Originally defined inside Jenkins
--- | --- | ---
Process environment variables handling: reset | Variable is reset to original value | Variable is removed
Process environment variables handling: removed | Variable is removed | Variable is removed