We used to have a metrics group "solr.jetty" but it's absent now on main & 9_0. I noticed this problem when running the prometheus exporter with the default configuration which output some errors relating to it not finding this. The fact that I'm seeing this shows we lack at least a sanity check (no errors) for the prometheus exporter default config. I think this is a release blocker. I'm putting this aside now but perhaps someone knows what happened to it?.
~ David Smiley Apache Lucene/Solr Search Developer http://www.linkedin.com/in/davidwsmiley
