Currently, a client wiki will show language links based on its own sitelink group. The wiki's own site group is a sensible default, but will not work for all cases.
Point in case is wikimedia commons: commons should not be in the wikipedia group (which would mean that it would show up a sa language link on wikipedia), but wikipedia should be the group shown on commons.
Marking as blocker because this blocks deployment on commons, which is scheduled.
Version: unspecified
Severity: blocker