There seems to be some misinformation here. Plasma Mobile does not require an Android stack. The Nexus 5 example of Plasma Mobile is indeed built on top of an Android (Cyanogenmod) stack, similar to how Sailfish ports use Cyanogenmod for hardware adaptation. If you pick a device which has drivers that only exist for Android, expect it to use Android components. Other ports of Plasma Mobile, including x86 and Raspberry Pi, do not use Android components.