The community metrics are provided with the help of Bitergia ( https://bitergia.com/ ).
Korma was a homegrown solution of them, they have switched to a more modern stack based on ElasticSearch/Kibana. The replacement is thus: https://wikimedia.biterg.io/
The Gerrit review queue is now https://wikimedia.biterg.io/app/kibana#/dashboard/Gerrit-Backlog
you are welcome