The validation of credentials dropdown is not working anymore. A couple of example where I noticed this are the git plugin GitSCM configuration and the github branch source plugin GitHubSCMSource configuration. I am talking about those doCheckCredentialsId implementations in plugins that use a credentials dropdown selector:

• https://github.com/jenkinsci/git-plugin/blob/git-4.11.3/src/main/java/hudson/plugins/git/UserRemoteConfig.java#L126
• https://github.com/jenkinsci/github-branch-source-plugin/blob/1637.vd833b_7ca_7654/src/main/java/org/jenkinsci/plugins/github_branch_source/GitHubSCMSource.java#L2127-L2135

More generally, when opening the browser console in Network tab and then opening Manage Jenkins > Configure System, we don't see any checkCredentialsId anymore although there used to be tons of them. Which leads to a more general regression in maybe the credentials plugin or core.