To get Cast3M files (*.dgibi and *.procedur) and Esope files (*.eso)
syntax highlighting in Kate (and Kwrite) editor,
all you need is to add the gibiane.xml and esope.xml files
in the appropriate syntax/ directory.

Custom .xml highlight definition files have to be copied to the 
org.kde.syntax-highlighting/syntax/ directory 
usually located in your user folder
(i.e. ~/.local/share/org.kde.syntax-highlighting/syntax/).
It can also be found among the paths listed by the command:
$ qtpaths --paths GenericDataLocation 

It is usually $HOME/.local/share but sometimes the directory
/usr/share/org.kde.syntax-highlighting/syntax/ also exist (You may have
superuser privileges to write in).

In previous Kate version, it was located at ~/.kde4/share/apps/katepart/syntax/
and the syntax directory had to be created.

On Windows® these files are located in %USERPROFILE%/AppData/Local/org.kde.syntax-highlighting/syntax
where %USERPROFILE% usually expands to C:\\Users\\user.

As a last step, at first use of Kate with a Cast3M or Esope file, 
you probably have to choose the appropriate syntax-highlighting in the tools menu.
Then save the file. The next opening of such a file will automatically
detect the correct highlighting.

More Explanation on https://docs.kde.org/stable5/en/applications/katepart/highlight.html