There are the technical elements -- what many HN readers are familiar with in terms of development, back-end, front-end, and infrastructure tools.
There is the art of developing the content in the first place, including the methods in this case of investigative journalism.
There is the whole maelstrom of business models and monetisation, on which virtually all attempts have been foundering of late.
But there's also the legal side, both offensive and defensive. Pursuing sources, information, and disclosures. And defending the publisher against attacks, such as the one described here. The publication of Permanent Record highlights another element, that of contracts and publication risk when faced with a state-level actor and an alleged NDA privilege. There are famous battles against defamation or censorship lawsuits. And there is the pursuit of others who take content without payment or credit, claiming it for themselves.
In many histories of great publishing events and episodes, lawyers (and publishers with spinal, intestinal, and gonadal integrity) play a huge role, and publishing houses or newspapers as much respected for their solicitors as their journalists and editors.
It's not just a business that concerns getting words on a page, or screen. The words have to matter, the words have to be right, the lights must be kept on, the words distributed. And, if your business is afflicting the comfortable and comforting the afflicted, resisting and challenging some very motivated and extraordinarily capable adversaries.
This is something advocates of "citizen-based journalism", or peer-to-peer or federated technologies, or DIY technical solutions, of whom I very much count myself as a former and current member, have long failed to appreciate.
The Mail & Guardian's message here is one to remember.