Identifying a an instance over the time is critical for a support team
Today this information isn't available. We have the URL which could be used (when it doesn't change)
We should probably expose the InstanceId and the LegacyInstanceId
https://wiki.jenkins-ci.org/display/JENKINS/Instance+Identity
https://javadoc.jenkins.io/jenkins/model/Jenkins.html#getLegacyInstanceId--
There is the legacy instance ID. And also the InstanceIdentity: https://github.com/jenkinsci/jenkins/blob/jenkins-2.176.2/core/src/main/java/jenkins/model/identity/InstanceIdentityProvider.java
The PR: https://github.com/jenkinsci/support-core-plugin/pull/183