Generic highlighter ignored?

[thuja_thuja]

Hello,

I am trying to get glsl syntax highlighting the same way as described here http://renderingpipeline.com/2013/12/glsl-syntax-highlighting-for-opengl-4-4/

I also disabled the GLSLEditor Plugin.

However I get no highlighting at all. I also tried writing my own Kate Syntax Highlighting File as described here https://doc.qt.io/qtcreator/creator-highlighting.html but Qt seems to ignore whatever I put in the generic-highlighter folder.

What am I missing?

Thanks,
Julian