If Aaron's crime revolved around breaking a use agreement by downloading in bulk, and trespassing by stashing a laptop making those bulk downloads in a known-unlocked-utility shed, what "network vulnerabilities" would even have been be germane to the case and thus included in MIT's filings?

Not only am I curious about what the vulnerabilities are (in general), I'm more curious as to why they were ever sent.

Is it just email where network engineers mused about known-vulnerabilities while discussing 'how Swartz got on the network'? Or was MIT making additional accusations against Aaron, that they would prefer to let plunge down the memory hole to avoid being seen as having been party to the prosecution trying to 'throw the book' at Swartz?

A document saying that any device can get on their network, and that it is deliberate policy to allow that, already is in the public record --- aaronsw's father read from it at the recent media lab memorial.

That said, it's possible that a general document sweep, answering a subpoena, also swept up documents describing, say, internal routing policies, or technical measures protecting access to student records, or something like that, which would be tangentially relevant to the case, and which they would have some legitimate interest in keeping to themselves.