Kube is a touch-friendly email app based on KDE technologies, read more on:
- https://cmollekopf.wordpress.com/2016/01/23/the-year-of-kube/
- https://mbohlender.wordpress.com/2015/12/18/a-little-kube-says-hi/
Jens and Thomas are working closely with Christian Mollekopf and Michael Bohlender on this.
If you want to make Kube work nicely on Plasma Mobile you can follow the instructions for Kube development : https://kube.kde.org/join.html