KDE's Plasma Mobile Switches Off Directly Using The Ubuntu Touch Stack
Plasma Mobile was originally based upon Ubuntu Touch but with the Unity and Mir components removed. Under the revised architecture, they will be relying upon Cyanogenmod/AOSP (Android Open-Source Project) directly as their base Android system. Ubuntu/Neon will then run inside a chroot or container. Yes, Ubuntu Touch also uses Cyanogenmod/AOSP.
Plasma Mobile began diverging from Ubuntu Touch upstream when they began pulling in newer Qt, switched to using upstream libhybris, and making other changes. The shift in their base system architecture will reportedly allow the KDE developers to more easily run Plasma Mobile with any OS, run Plasma Mobile hopefully on every device supported by CM, and to have more control over the Android stack for Plasma.
Those interested in learning more about Plasma Mobile's new base architecture can see this blog post by KDE developer Bhushan Shah.