It might depend on what .ks files are. I don’t know of any of the builtin language lexers that expect that file extension, but I don’t know all the lexers myself.
In general, if there isn’t a builtin lexer, you will have to create a User Defined Language (UDL).
Official docs UDL overview: https://npp-user-manual.org/docs/user-defined-language-system/ Detailed UDL description: https://ivan-radic.github.io/udl-documentation/There is a community-supplied collection of UDL at https://github.com/notepad-plus-plus/userDefinedLanguages/blob/master/udl-list.md , which you can download as described in the official docs UDL overview… but I don’t see any there that immediately jump out and say “I use the extension .ks”