The light-switch housing was designed by Dave, you can find the files to laser-cut another one on github in the laserwarez.
Niklas added 3d printable inserts, to change text on the inserts you can use the following open SCAD File: https://files.x-hain.de/s/n3d4F4FZmADekjj
while slicing the inserts you can define a filament change at 6mm height to print the text in a different color.