cc @schoenbaechler
Here has an app widget overview from Android Developers: https://developer.android.com/guide/topics/appwidgets/overview

Things I would like to bring up:

• If the widget requires too frequent API calls, for example, suggested edits of "translation" type, especially for non-English users, it may drain the battery so bad.
• The user can resize the widget, so please consider making layouts that are resizable.
• Create a preview image of the widgets, which we currently don't have.
• The theme options might be a separate thing from the app, but this is not really required.

Thx for the overview, @cooltey — I like the resizing/responsive design part!