There is a way for anyone to see ♦ moderator announcements despite not being one:
This can be done by creating a Stack Overflow team (which is now free!), then going to https://stackoverflow.com/c/{team-id}/topbar/mod-inbox
. (I added in a few stylesheets in the screenshot to make the above screenshot look good). Avoid doing anything remotely like a moderator action in this new team, since having done moderator actions can make this page 500.
It doesn't seem like any of the announcements have any particularly secret info in them (they seemed pretty mundane to me), but it seems like making these public is a Bad Idea.
This is happening because Teams admins are actually moderators in disguise (with a bunch of stuff changed).