Q4OS is a lightweight distro built around the old-school Trinity Desktop Environment (TDE), an open-source initiative that tries to keep the spirit of the KDE 3.5 desktop environment alive across all GNU/Linux distributions, and while it’s been engineered to run on 32-bit and 64-bit PCs, there are also Raspberry Pi builds available. It looks like the PINE64 port is based on the Debian GNU/Linux 8 “Jessie” operating system, which means that it’s derived from the stable Q4OS 1.8 series of the distribution. It includes a Liux kernel that has been optimized for PINE64 single-board computers.