The Robotron Z1013 was an East German (GDR) home computer first released in 1985. It had similar capabilities to the ZX81, with monochrome character based graphics and no sound. It was based around the U880 CPU, a clone of the Z80, clocked at 1mz.
Now we have the possibility to check this system out in our STmini. You can download the core files here:
https://github.com/boert/Z1013-mist