Similar to what was done in the fix for https://issues.jenkins-ci.org/browse/JENKINS-25164 (https://github.com/jenkinsci/jenkins/commit/4bab3630efcc2fa331db2989e321d9af1b8cdc1c) with the addition of the JOB_BASE_NAME env var, I'd like to see the addition of a JOB_DIR_NAME env var containing the dirname of the full job name (i.e. 'bar' for a job name 'bar/foo').

The reasoning is that the job structure (i.e. the name of the folder containing a job) usually represents meaningful organisational information that a job might want to act upon.