The admin monitor message style was changed some years ago but some plugins are still lagging behind. It could be nice to have a taglib provided by Jenkins core directly to prevent plugin need to adjust everytime.

This occurs once yes, but it's in order to remove the need for future change. We should do that for "all" of the possible similar cases. This will also help core style/UI update without breaking plugins.

Example: GH search => GerritAdministrativeMonitor