Kiwix also offers a physical product just like this that comes in a few different flavours: https://kiwix.org/en/kiwix-hotspot

This prepper disk is almost assuredly just Kiwix server on a raspberry pi.

It isn’t, actually. Kiwix, IIAB, Rachel, and a custom web interface and search implementation- along with licensed and commissioned content. Kiwix is cool (and a partner of ours) but a Prepper Disk is a lot more than Kiwix.

Here are some Kiwix datasets for preppers https://library.kiwix.org/?lang=eng#lang=eng&tag=preppers (you may have to clear the URL params if you don't see any results)