If you "stumbled across a local government website", you cannot "anonymously leak" it anymore, since your IP address is already on the web server's logs. After an "anonymous leak", it's the first place they'll look.
The only good alternative is to keep quiet, and pray that nobody else finds it and anonymously report it to the press before the logs containing your IP address are rotated and deleted.
The only good alternative is to keep quiet, and pray that nobody else finds it and anonymously report it to the press before the logs containing your IP address are rotated and deleted.