Before implementing support for article collection files such as Kiwix files, we need to define how offline collections will be used within the app.
Some areas to think about:
Download size requirements
Do larg downloads need to be reumsable?
Do users need to get Incremental updates or redownload the whole file
Wifi / cellular
Prepackaged collections? or also defined by users?
How do users browse for new collections?
How do users browse downloaded collections?
How do users know if an update to a collection is available?
How do users know if a particular article is up to date or an update is available?
Related: these seem somewhat natural to mix with the reading list UI in the android app. Or another way to put it, these offline "lists" may compete or be conflated with existing reading lists, so it's probably best to use the same metaphor and augment the existing UI