OpenTES Arena is an open-source engine recreation of The Elder Scrolls: Arena, the 1994 first-person RPG from Bethesda that launched the long-running Elder Scrolls series. The project, maintained by afritz1 on GitHub, aims to reimplement the original game engine in modern C++ so players can run Arena's original data files on contemporary PC hardware.
Like similar decompilation and recompilation efforts for other classic titles, OpenTES Arena is not a remake or a patch but a ground-up engine reimplementation. It targets PC and requires the player to supply their own copy of the original game data to play.