Kate comes with default file associations for syntax highlighting; most of them are correct, but some need to be changed (example: *.pp is associated with Pascal, but should be assigned to Puppet). These associations can be changed as follows:

1. In Kate, open the menu "Settings" → "Configure Kate..." → "Editor Component" → "Open/Save" → "Modes & Filetypes".
2. Correct the file extensions for different source types, and save the settings.

That's it... The settings done in Kate influence all katepart components, hence also the default behaviour for different KDE applications.

Sources

• http://unix.stackexchange.com/questions/137989/how-to-change-default-syntax-highlighting-for-header-file-in-kate