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
Should images be included?
Do large downloads need to be reumsable? What happens if a 500 Mb download is interupted 80% complete?
Do users need to get Incremental updates or redownload the whole file?
Can incremental updates be implemented client side (Also define "incremental")?
Do we need to persist the downloaded file the device?
Wifi / cellular restrictions?
Prepackaged collections? or also defined by users?
How do users browse for new collections? Native? In app? Web? Where are they hosted?
Should wmf be able to generate collections? Edit them? What about volunteers? End users?
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?
How does the UI from Reading Lists differ from the UI for Offline Collections in apps?
How does the functionality of Reading Lists differ from Offline Collections?