Understand Grand Juries are to be secret, but look at the leaks from the Lib cases.
Grand jury participants are all sworn to secrecy, EXCEPT witnesses that testify to the grand jury. That’s why there are ‘leaks’ whenever there is a politically charged grand jury. Some witnesses will publicize what they were asked about.
Reporters monitor courthouses, looking for high-profile people entering or leaving when a grand jury is thought to be in session. This info is then sometimes embellished into a ‘leak’.
BTW, the feds issue more than 80,000 indictments per year.
Sealed indictments means no public revelation of who and how many people are charged, or which and how many charges. Once an arrest has been made, both the arrest and indictment are made public.