I can't find that setting in the "Git plugin" section in the /configure page. I only see "user.name", "user.email", "Create new accounts base on author/committer's email". Could you point to where to find that setting? Also, it'd be useful to see how to do this in a Jenkinsfile pipeline.

It looks like this setting `authorOrCommitter` has been moved back in 2013 to some "Extensions". Where can I find them? Is it a separate plugin?

Your pipeline definition needs to use the more general purpose "checkout" step rather than the "git" step.  You can use the "pipeline syntax" on most pipeline job pages then choose "checkout" from the dropdown and define the git checkout definition, with full support for extensions.,

I am already using the "checkout" syntax:

checkout([$class: 'GitSCM',
  branches: [[name: 'snip']],
  browser: [$class: 'GithubWeb', repoUrl: 'snip'],
  doGenerateSubmoduleConfigurations: false,
  extensions: [],
  submoduleCfg: [],
  userRemoteConfigs: [[snip]])

Where can I find the documentation for the available options?

Now I see that I can choose "Use commit author in changelog" under Additional Behaviour. Thanks!

Where exactly is this option? I have looked everywhere and cannot seem to find it.

I am using the `checkout scm` step in Blue Ocean rc3 if that helps.

The "pipeline syntax" link on most pipeline job definition pages will let you choose the "checkout" step. That will then guide you through the web page to select various git plugin options. Look for "Additional Behaviours" and you'll find a drop-down list which includes "Use commit author in changelog".

We were tempted some years ago to make "Use commit author in changelog" the default, but any change to default behavior tends to result in a loud outcry from users who don't expect defaults to change from one release to the next.

According to this article: https://support.cloudbees.com/hc/en-us/articles/226122247-How-to-Customize-Checkout-for-Pipeline-Multibranch the "Additional Behaviours" should appear in Branch Source -> Git, but in branch source I only have GitHub available, which doesn't have this option.

Additionally, I want to change the behaviour for all projects if possible and not have to redo this setup on each one (especially since they are created automatically from pushes to the organizations repos).

I understand the need for backward compatibility, but since pretty much all commits in GitHub are made by "noreply", there should at least be a way to change the behaviour globally (JAVA_OPTS?)

I'm not clear which type of pipeline job you're using, since you say that GitHub is the only branch source available.

If you're using a GitHub Organization Folders job, then the customization of checkout technique will need to be performed either in a pipeline global library shared with all jobs, or in each job.

If you're using a pipeline multi-branch job, then the customization of checkout technique can be performed at job definition, and may then be adjusted or modified in either a pipeline global library shared with all jobs, or in the Jenkinsfile for each branch.

Since I am using pipeline multi-branch jobs with GitHub, I will add a helper to our shared libraries as you suggested. Thank you very much for your help!

(I still think however that there should be a way to globally override the default checkout behaviour since it is incompatible with the largest Git provider on the planet)