The TDE project began as a continuation of the K Desktop Environment (KDE) version 3. The name Trinity was chosen partly because the word means "three" and TDE was a continuation of KDE 3. TDE now is its own computer desktop environment project. Equipped with a suitable collection of desktop effects that remain compatible with older hardware. Responsive on older hardware, while also being compatible with newer hardware. Compatible with, but not requiring, 3D acceleration (unlike KDE Plasma). Compatible with freedesktop.org and Linux file system hierarchy standards. Compatible with other desktop environments.

RSS: https://www.trinitydesktop.org/rss.php

Looks like there's a third party Arch package repository for TDE: https://wiki.trinitydesktop.org/Arch_Trinity_Repository_Installation_Instructions