It’s not clear to me what happens to reports during this period. I expect admins have some way to see them, but it’s not clear how visible they are or whether admins take action on them.

Within each instance, there is a single report generated, that can be seen by everyone who has the right "scope". Admins see all reports that make it to their instance, and moderators see reports for communities that they moderate.

Which means that if you report something for an unmoderated community, the admins will see the report. If it breaks instance rules, they will likely act, but if breaks community rules but not instance rules, they'll just ignore the report