Hello,

I would like to test my syntax highlight xml-file for kate.

My problem is that I am not able to pick / find my file under in menu (Tools -> Highlighting -> ...)
My file is saved in the following directory: C:\Users\***\AppData\Local\org.kde.syntax-highlighting\syntax

Are there any further steps necessary to include my xml-file into kate or did I have made a mistake?

Thanks for your help

The one thing that comes to my mind is you probably need to restart Kate for it to pick up the new syntax file.
Besides that, just double-check that the (xml) syntax is correct and that the metadata parts of your syntax file are updated as expected.