Is there a way to show app badges with numbers?
E.g. what mail or gmail does (in iOS, not sure what Android does) to show number of unread messages. It's like badges in a footer, but at the app icon.
Very interested in this as well.
Not currently. You could submit an issue and see if this is something Ethan is interested in adding. Within an app, you can add numeric badges to the top-right of the header and to footer tabs, but currently not at the app icon level.