halium is a project (since 2017) to unify the hardware abstraction layer for projects that run GNU/Linux on mobile devices preloaded with Android.
Over the past few years, several other companies (pinephone, Purism Librem, postmarket OS) started working on open source mobile hardware projects and provided better architecture plus no binary blobs.
After careful consideration of the current situation, the developers of the KDE Plasma Mobile User Environment for Linux Phones announce on December 14 that they will drop support for Halium and focus on supporting Linux kernel versions closest to the main one.
Source: linux.org.ru