Words mean what we say they mean.
https://en.wikipedia.org/wiki/United_States_diplomatic_cables_leak
According to The Guardian, all the diplomatic cables were marked “Sipdis”, denoting “secret internet protocol distribution”, which means they had been distributed via the closed U.S. SIPRNet, the U.S. Department of Defense’s classified version of the civilian internet.[14] More than three million U.S. government personnel and soldiers have access to this network.[15] Documents marked “top secret” are not included in the system. Such a large quantity of secret information was available to a wide audience because, as The Guardian alleged, after the 11 September attacks an increased focus had been placed on sharing information since gaps in intra-governmental information sharing had been exposed.[14] More specifically, the diplomatic, military, law enforcement and intelligence communities would be able to do their jobs better with this easy access to analytic and operative information.[14] A spokesman said that in the previous weeks and months additional measures had been taken to improve the security of the system and prevent leaks.[14]
https://en.wikipedia.org/wiki/SIPRNet
The Secret Internet Protocol Router Network (SIPRNet) is “a system of interconnected computer networks used by the U.S. Department of Defense and the U.S. Department of State to transmit classified information (up to and including information classified SECRET) by packet switching over the TCP/IP protocols in a ‘completely secure’ environment”.[1] It also provides services such as hypertext document access and electronic mail. As such, SIPRNet is the DoD’s classified version of the civilian Internet.
SIPRNet is the SECRET component of the Defense Information Systems Network.[2] Other components handle communications with other security needs, such as NIPRNet which is used for nonsecure communications, and JWICS which is used for Top Secret communications.
According to the U.S. Department of State Web Development Handbook, domain structure and naming conventions are the same as for the open internet, except for the addition of a second-level domain, like, e.g., “sgov” between state and gov: openforum.state.sgov.gov.[3] Files originating from SIPRNet are marked by a header tag “SIPDIS” (SIPrnet DIStribution).[4] A corresponding second-level domain smil.mil exists for DoD users.[5]
According to the Pentagon, SIPRNet has approximately 4.2 million users.[6] Access is also available to a “...small pool of trusted allies, including Australia, Canada, the United Kingdom and New Zealand...”[7] This group (including the US) is known as the Five Eyes.
SIPRNet was one of the networks accessed by Chelsea Manning, convicted of leaking the video used in WikiLeaks’ “Collateral Murder” release[8] as well as the source of the US diplomatic cables published by WikiLeaks in November 2010.[9]
Hillary claimed that couriers delivered things and that she went to meetings. Are there minutes from those meetings? Are there signed receipts of the documents she viewed and responded to by courier? Certainly those documents should be retained in an archive somewhere.