We turn various online educational contents (such as Wikipedia, for example) into ZIM files, and these can be opened by Kiwix even if you have no connectivity whatsoever.
The ZIM file format is an open file format that stores website content for offline usage.[1] The format is defined by the openZIM project, which also supports an open-source ZIM reader called Kiwix. The format is primarily used to store the contents of Wikipedia and other Wikimedia projects, including articles, full-text search indices and auxiliary files.[2][3]
Here’s one way to help: https://kiwix.org/en/about-us/#our-story
Download Wikipedia to your own device. If it’s ever blocked or taken down you still have access and can help share information with others.
You can download different versions (e.g. without images) and different languages based on your needs.
There’s other resources available via kiwix as well but I’ve not really explored them to be honest
Does it run a local web server or is it all static files? Is it searchable?
https://flathub.org/apps/org.kiwix.desktop
https://en.wikipedia.org/wiki/ZIM_(file_format)