Macintosh Application Environment
The Macintosh Application Environment (MAE) is a software package introduced by Apple Computer in 1994 that allows certain Unix-based computer workstations to run System 7 and its application software. == Overview == MAE uses the X Window System to provide the Macintosh Finder graphical user interface in a window.
Source: Wikipedia — Macintosh Application Environment (CC BY-SA 4.0)