The z1013 is a product of the socialistic German Democratic Republic. During the 80ies, attempts were made to compete with western electronics, but they were limited by production costs and limited supplies. Some aspects of the computers of those times were copied from western technology.
The z1013 was sold as DIY kit, with the mainboard pre-assembled. The previous user created a casing for the mainboard, forwarding essential connectors and adding additional peripherials.
The extra wires on the bottom side came from factory. Later changes to the Layout were to expensive to change the machines and edit the production templates, so it was considered cheaper to apply manual fixes to every produced board.
The keyboard was home-produced. At the time of its creation it was commonplace to hard-draw the routes on your circuit boards and etch them yourself.
As of 2020, i did not get the board to produce video output. The screen shows static for one or two seconds and then blanks out. I also dont have access to an oscilloscope to check whether there is bus activity.