Secure Messaging is a new innovation for confidential story-sharing and source protection, underpinning the Guardian’s commitment to investigative journalism. The Guardian has published the open source code for this important tech to enable adoption by other media organisations.
I think they are bundling this into their regular app, so they’d have to put every guardian read on the list😅
Yep, that’s the point described in the linked paper - traffic goes via the same domains used for their app, and the messenger is embedded in their app