Does it go to the mods of the community that the comment is in? Does it go to the admins of the instance that community is in? The admins of the instance I’m logged into? All of the above?
The admins can see it all afaik (within their own instance), but usually its the mods acting on stuff (within a community), and the admin only steps in if the community mod/mods is/are dropping the ball.
Okay, that makes sense the more I think about it. That’s what mods are for, ultimately.
the mods of the community that the comment is in
This, unless this has changed.
So how can we report to the admin of our instance another "problematic instance?
Contact an admin of your “home” instance.
Admins will also see the reports, not only the community mods. In fact even admins from other instances will see them, which sometimes is a bit confusing.
send a message to the admin(s)
You can’t. You should reach out to the mods/admins on the other instance.
You can compare it with e-mail.
When you get an angry mail from company B while you work at company A, there’s not much somebody at company A can do about it, except blocking the mails from company B.If it’s a very problematic instance the admins can choose to block federation between their instance and the other instance.