Temporary accounts configuration has an option for known=true (while enabled=false). This is intended to be used as an "off-switch" for wikis that enabled temp accounts but need to disable temporary account auto creation.
For metawiki, it would make sense to pre-emptively set known=true for the feature while we deploy to pilot wikis, because:
- Users will probably expect to be able to use Special:GlobalContributions on metawiki to see temporary account contributions, and access is likely going to be gated on temp accounts being known
- Some form inputs may only accept temporary account usernames if the temp account config is known