It would be helpful for debugging/troubleshooting purposes if the Git plugin logged the version of git being used (i.e., the output of git --version) to the console before starting the cloning process. Additionally, if the version of git being used is not supported by the plugin, a warning should be logged to the console.

One practical application of this would be a situation like JENKINS-62534. We were not aware that our Jenkins master agent was still running git 1.8.

Possible Solution (modeled after GitHub Webhooks Warning)

When alerts are needed for unexpected global conditions in the git plugin, it could be done through a similar user interface technique as is used by GitHub webhooks. A number appears in the top right of the Jenkins interface. When that number is clicked, a dialog appears that includes a "View" button that would open a page that lists all the problems of that type. The "Dismiss" button would clear the contents of the page that lists all the problems of that type.