This ticket is specifically for the new replicas design work + Database Reports. See T270407 for the epic.
Announcement: https://wikitech.wikimedia.org/wiki/News/Wiki_Replicas_2020_Redesign
With this new system, we can no longer connect to any database through the same connection. Rather, we either create a new connection for each desired database, or in the case of "global" tools like XTools, we connect to the appropriate slice, going by https://noc.wikimedia.org/conf/dblists/[slice].dblist, for example https://noc.wikimedia.org/conf/dblists/s7.dblist
More info: https://lists.wikimedia.org/pipermail/cloud/2020-November/001294.html