The entirety of the meshtastic project is web first.
- To flash your boards, the suggested method is their "Web Flasher", and if you download the firmware source, it depends on PlatformIO (and the internet) to download and install the toolchains and flasher programs you need.
- The clients for meshtastic are available on the app stores, or as a web app at https://client.meshtastic.org/ None of these are offline. I did later learn the boards themselves host the web app, but they still have to be connected to an Wifi AP, you don't get it just by plugging the board into your computer.
- The docs are hosted at https://meshtastic.org/docs. "Download Docs" or "How to self host this project" are not topics described there or anywhere else. A technical person could figure this out, but this is seemingly not a primary concern.
I suppose this is the very point of this post, to get people to have it all set up beforehand, but not even having the docs as a PDF I can read offline? I learned about Meshcore too in this thread, but if I go to their site and the "getting started" guide is a Youtube video, then you're not ready for an emergency!