On a plain install with MediaWiki core (such as in the QUnit builds), the Jenkins build log show this PHP error:
PHP Warning: No route to fetch banner choice data configured. [Called from CNBannerChoiceDataResourceLoaderModule::getChoices in /mnt/jenkins-workspace/workspace/mwext-CentralNotice-qunit/src/extensions/CentralNotice/includes/CNBannerChoiceDataResourceLoaderModule.php at line 57] in /mnt/jenkins-workspace/workspace/mwext-CentralNotice-qunit/src/includes/debug/MWDebug.php on line 300
This may be due to the modules we're testing having as a dependency the banner choice resource loader module.
In any case, it's not serious, only annoying, since it doesn't affect the ability of the job to detect actual QUnit failures or successes: