Culprit:
FlowGraphTableAction/index.jelly#L33-L35

Reproduction steps:

• Install Pipeline: Job or clone https://github.com/jenkinsci/workflow-job-plugin and then mvn hpi:run
• Create a Pipeline with the following script:

   sleep 5000
  

• Save
• Build your job
• Go to your build
• On the side-panel click on "Pipeline Steps"
• Every 5 seconds, your steps should be updated with an increase of their duration

Screenshot attached about where the feature is displayed.

Proposal
https://www.jenkins.io/doc/developer/security/csp/#inline-javascript-blocks

Testing notes

• Ensure to reproduce the feature before any change
• Ensure that you reproduce the feature after you have made the change