Kiwix

Kiwix is an offline wikipedia viewer. See the official site: https://kiwix.org/

You need to download an archive (ZIM file) from https://download.kiwix.org/zim/, store it in on your device, and manually select it after starting the extension.

You can search among the article titles, and read any of them without any Internet access.
All the content of wikipedia is inside your device (including the images).
It might also works with other content in the OpenZIM format: https://openzim.org/wiki/OpenZIM , but has been only tested on the wikipedia ones.

If your Internet access is expensive/rare/slow/unreliable/watched/censored, you still can browse this amazing amount of knowledge and culture.

3.1.0
* NEW: Low-level block cache significantly improves binary search speed, and can speed up resource loading in most browsers
* NEW: Archives with WebP-encoded images are now decoded in legacy browsers via a polyfill
* UPDATE: Images are now extracted sequentially in jQuery mode from the top of the DOM
* BUGFIX: Running binary searches are now cancelled completely if user enters new search term or navigates away
* BUGFIX: Active content warning was erroneously showing on some ZSTD WikiMedia landing pages in jQuery mode

3.0.0
* NEW: Add support for reading ZIM archives compressed with the zstandard compression algorithm
* UPDATE: Make Privacy Policy publicly accessible

2.8.0
* NEW: Intelligently select the best Storage API for storing settings between sessions (cookie or localStorage)
* NEW: Display title search results progressively instead of waiting for search to complete before displaying them
* NEW: User can change depth of title search from Configuration
* UPDATE: Better handling of case in title search, returning more accurate search results
* UPDATE: Use const to declare constants, enabling better app memory management
* UPDATE: Use SameSite=Strict for any residual cookie usage to conform to new security standards
* BUGFIX: Major blocking bug causing high memory usage and slow load times when reading MIME type table of recent ZIM archives

2.7.0
* NEW: Selectable dark mode for app UI and for articles (does not work on IE11)
* NEW: Optional transition between app pages
* NEW: Native asset caching in Service Worker mode – considerably speeds up article load times in some contexts
* UPDATE: Privacy Policy
* UPDATE: Minor changes to Kiwix icon
* UPDATE: Bootstrap updated to v4
* UPDATE: Q Promise library updated to v1.5.1
* UPDATE: Various code simplifications and cleanup
* BUGFIX: Support details-summary tags to ensure all article subheadings are open in jQuery mode
* BUGFIX: Broken display when search results have special characters
* BUGFIX: Display of random article fragments when using back/forward buttons quickly
* BUGFIX: Several UI bugs (search results disappearing, redundant scroll bar)

2.6.0
* Support for imagemaps (area tags) in jQuery mode, like for maps in wikivoyage
* Enable keyboard selection in search results
* Drag and drop support of ZIM files (on desktop)
* Support download of epub files (for Gutenberg ZIM files) and some other types of downloads
* Generic handling of MIME Types, instead of the previously hard-coded ones
* Add explanations and detect when there are CORS issues when running kiwix-js through file://
* Fix for some cache issues in ServiceWorker mode
* Some fixes for filenames with question marks, hyperlinks with hashtags, articles with no title, and articles with special characters in their URL

2.5.0
* Better support of Javascript in pages
* Preliminary support of video/audio content (including subtitles)
* Better spinner

2.4.0
* Significant performance improvement
* Stability improvement for the ServiceWorker mode

2.3.1
* Fix excessive memory consumption
* Fix SVG file handling
* Add favicon