Proposed enhancement to answer the need for the Jenkinsfile runner (see here).

The $JENKINS_HOME/init.groovy.d directory should be customizable via a system property.

Open question: should this be more global and treat the other (known) types of hook scripts, or targeting only init scripts? If I believe the comments in the linked PR, other types of scripts might be needed by the JFR so it might be worth to go global.