I have used the Blue Ocean plugin to create a Jenkins job that automatically uses the Jenkinsfile (declarative pipeline) to build and report the status back to GitHub. That all works fine.

The issue I have is that I cannot get old builds deleted. The job shows as a repository and I have configured it to keep a maximum of 5 builds. But I noticed that the branches indexed, including the master branch, also have their own configuration. I tried setting up the old builds deletion but there’s no save button! I thought this was because the configuration propagates from the repository to the branches, but it has no effect. How can I get this to work?