The BlueOcean interface is to be installed via a plugin aggregator which in turns depends on every single BlueOcean plugins written to add support for various plugins such as Jira, GitHub. We then have way too many plugins installed.

Upstream Jenkins has an issue filled about it: https://issues.jenkins-ci.org/browse/JENKINS-42502 , the recommendation is to uninstall the BlueOcean aggregator plugin which in turn would let us remove the other plugins we do not need. The caveat is that we will have to ensure all the BlueOcean plugins are at the same major version.