Halium is based on libhybris, to my understanding that was developed when Nokia stopped making Linux phones and some of their developers started making their ow

Halium is based on libhybris, to my understanding that was developed when Nokia stopped making Linux phones and some of their developers started making their own under the name Jolla/SaifishOS in 2011. While Nokia could maintain their own Linux kernel that's impossible for a small vendor/team. There is no realistic alternative to taking the Android kernel provided by the SoC vendor.