At the Randa Meeting 2017 Volker and I decided to write a little KWin plugin. Activating this plugin you can simulate various types of color vision deficiencies, either on individual windows or full-screen. The plugin works by running a fragment shader on the respective window/screen.
Here is a short video demonstrating what we did:
The purpose is to allow everyone to test applications problematic color schemes. https://en.wikipedia.org/wiki/Color_blindness